Upper Back Pain on the Left Side: Muscle, Rib, Gas, Lung or Heart?

It starts as a nagging ache just inside your left shoulder blade. Maybe you noticed it after a long day at the laptop, after carrying a heavy bag on one shoulder, or after a big lunch that left you bloated. Then a worrying thought creeps in: the heart is on the left side, so could this be the heart? You press the spot, it hurts, and you are still not sure whether to rub on some balm or rush to a hospital.

Most left-sided upper back pain comes from muscles and the small joints where the ribs meet the spine, and it settles well with the right care. A smaller number of people have pain from the stomach, the lungs or the heart. This guide explains the clues for each cause, the warning signs that need emergency help, and what upper back pain left side treatment looks like once serious causes are ruled out.

What sits under the left upper back?

The upper back is the thoracic spine: twelve vertebrae, each joined to a pair of ribs, covered by layers of muscle around the shoulder blade. Under the ribs lie the left lung and, in front, the heart. Just below the diaphragm sit the stomach, spleen and the tail of the pancreas.

Nerves from these organs share pathways with nerves from the back, so the brain can feel pain from the heart, lungs or stomach in the back. That is why a good doctor asks not only where it hurts but what else is happening. For a broader look at pain felt right on the spine, see our guide to backbone pain and what it can mean.

Muscle causes: rhomboid and trapezius strain

The rhomboids run from the spine to the inner edge of the shoulder blade. The trapezius spreads from the base of the skull across the shoulders and down the middle of the back. Overloaded, these muscles ache, tighten and form tender knots called trigger points.

Common triggers include:

• Desk and phone posture. A laptop placed to one side, a mouse held far from the body, or a phone tucked between ear and left shoulder. Long hours of this also cause neck pain from screen time.
• One-sided loads. A heavy laptop bag or handbag always on the left shoulder, carrying a toddler on the left hip, or lifting a gas cylinder awkwardly.
• Sudden effort. Bowling in a weekend cricket match, a badminton smash, or pulling a stuck two-wheeler off its stand. These can cause a true muscle strain, explained in back sprain or strain.
• Sleep. Sleeping on the left side with the arm pulled under the pillow, or on a pillow that is too high. Our tips on the best pillow and sleeping position help here too.

Clues it is muscular: a dull ache or burning knot, a spot that is tender when you press it, pain that changes when you move your shoulder or arm, stiffness in the morning or after sitting, and relief from heat and gentle stretching. Sometimes the problem starts in the shoulder itself, such as a rotator cuff problem, with the back muscles working overtime to protect it. Widespread tender points on both sides with poor sleep and tiredness may instead suggest fibromyalgia.

Rib and spine joint causes

Rib joint sprain (costovertebral dysfunction)

Each rib forms two small joints with the spine. A twist, a heavy lift or a bout of coughing can strain one of them; people often say “a rib has gone out”. The pain is sharp, sits just beside the spine, catches on a deep breath or a twist, and may wrap around along the rib. Long coughing spells, for example during an asthma or allergy flare, are a common trigger.

Thoracic facet joints, discs and stiffness

The small joints at the back of each vertebra can become stiff and painful, much like the facet joint pain more familiar in the lower back. Age-related wear can also show up as thoracic spondylosis. Pain that starts in the lower neck can also spread to the inner shoulder blade, as described in pinched nerve in the neck.

Less common spine causes to keep in mind

• Compression fracture. In older adults, especially women after menopause or anyone on long-term steroids, a small fracture can happen with a minor fall or even a cough. Read about osteoporosis and back pain.
• Inflammatory back pain. Young adults with morning stiffness that eases with activity may have ankylosing spondylitis, which can also affect the rib joints and make deep breaths feel tight.
• Shingles. A burning, tingling band of pain on one side of the back and chest can come a few days before the blistering rash appears. It does not cross the midline.
• Infection. Back pain with fever, night sweats and weight loss needs checking for spinal infection or spinal TB.

Gas, acidity and stomach causes

Sometimes back pain really is “just gas”. Trapped gas where the large bowel bends under the left ribs can cause pressing pain in the left upper abdomen, side and back. Acidity, gastritis and stomach ulcers can cause a burning or gnawing pain that bores through to the back.

Clues it is the stomach: pain linked to meals or an empty stomach, bloating, burping, a sour taste, heartburn, and relief after passing gas or a bowel movement. Pain does not change much when you press the back or move your arm.

Gas pain in upper back treatment is usually simple: smaller meals, eating slowly, a short walk after food, cutting down fizzy drinks, very spicy or oily food and late dinners, and not lying flat for two to three hours after eating. A pharmacist or doctor can suggest a suitable antacid for occasional use. Frequent painkillers can themselves irritate the stomach, one more reason painkillers are not the long-term answer.

Two cautions. First, do not assume pain is gas if it comes on with exertion, such as climbing stairs or walking briskly, and eases with rest. That pattern needs a heart check. Second, severe, constant pain in the upper abdomen that spreads to the back, with vomiting, can be pancreatitis and needs urgent hospital care the same day. Pain lower down near the waist with urinary symptoms is a different story, covered in kidney stone pain or back pain.

Lung causes

The lining of the lungs (the pleura) is sensitive to pain. When it is inflamed, as with pleurisy or a chest infection, you feel a sharp, stabbing pain that is clearly worse with every breath in and with coughing. Pneumonia usually brings fever, cough and tiredness along with the pain.

Two lung problems are emergencies. A collapsed lung (pneumothorax) causes sudden sharp pain on one side with breathlessness, and can happen in tall, thin young adults and in smokers. A blood clot in the lung (pulmonary embolism) causes sudden breathlessness, sharp chest or back pain and sometimes coughing blood, especially after long travel, surgery, bed rest, pregnancy or a swollen, painful calf. Both need the nearest emergency department immediately.

Heart causes: when the back is not the problem

Angina or a heart attack does not always cause classic crushing chest pain. Some people, especially women, older adults and people with diabetes, feel pressure or aching in the left upper back, between the shoulder blades, in the left arm, jaw or upper abdomen, often with breathlessness, sweating, nausea or unusual tiredness.

Clues it could be the heart: pain brought on by exertion, stress, a heavy meal or cold weather; pain that does not change when you press the back or move your arm; and risk factors such as high blood pressure, diabetes, high cholesterol, smoking or a family history of early heart disease. If you have these risk factors, it is worth keeping an eye on your blood pressure readings, your lipid profile and your HbA1c and fasting sugar.

A sudden, severe, tearing pain between the shoulder blades can mean a tear in the main blood vessel (aortic dissection). Like a heart attack, it needs emergency care, not a back specialist first.

Upper back pain on the left side: cause, clue and what to do

How Dr Heal treats left upper back pain

Our back pain treatment begins by making sure we are treating the right problem. Once heart, lung and stomach causes have been considered, a typical plan looks like this:

1. Find the true source. A detailed history and a hands-on examination of the spine, ribs, shoulder blade and shoulder. If anything suggests the heart, lungs or stomach, we advise the right tests and the right specialist first. Blood tests and X-rays can be done in our in-house laboratory and radiology at our facilities.
2. Settle the painful muscle or joint. Most people improve with targeted manual therapy and exercise. When a stubborn trigger point or rib joint needs an injection, we use a regenerative preparation from Dr Heal Pharma that contains no steroids, painkillers or antibiotics, aimed at helping the tissue heal rather than simply masking pain. Read more about regenerative medicine and why we avoid repeated steroid injections.
3. Correct what keeps it coming back. Posture at the desk and on the two-wheeler, bag habits, pillow height, and shoulder blade muscle strength.
4. Look at the whole body. Through functional medicine and clinical nutrition, we check vitamin D and B12, blood sugar and thyroid, and work on sleep and stress, which keep muscles tight. Long-standing pain also affects mood, as explained in chronic pain, stress and low mood.
5. Guide your rehabilitation and follow up. A step-by-step exercise programme, reviewed until you can work, lift and sleep without the pain returning.

If your pain also involves the neck or shoulder, ask about our neck pain treatment and shoulder pain treatment, or browse all our treatments. You can also meet our pain specialists.

What you can do at home for muscle and rib pain

• Use heat. A warm compress or hot water bag for 15 to 20 minutes, two or three times a day, relaxes tight rhomboid and trapezius muscles.
• Keep moving gently. Slow shoulder rolls, shoulder blade squeezes, and lying on your side to rotate the upper body open like a book. Stop any movement that sharpens the pain.
• Breathe fully. A few slow, deep breaths every hour keep sore rib joints moving.
• Set up your desk. Screen at eye level and straight in front of you, mouse close to the body, and a break to stand and stretch every 30 to 45 minutes.
• Share the load. Use a backpack with both straps, or switch shoulders. Hold the phone in your hand or use earphones instead of trapping it on your shoulder.
• Build better habits. Our daily habits for a healthy spine are a good place to start.

If the pain is not clearly better in one to two weeks, keeps returning or disturbs sleep, get it examined. Our guide on which doctor to see and which tests you need explains what to expect.

Frequently asked questions

Can gas cause upper back pain on the left side?

Yes. Trapped gas and acidity can cause pain felt in the left upper abdomen and back, usually with bloating, burping or heartburn and a link to meals. Pain that comes on with exertion or with breathlessness, sweating or chest discomfort should never be blamed on gas.

How do I know if my left upper back pain is from the heart?

Heart pain is usually a pressure or heaviness, brought on by effort or stress, and does not change when you press the back or move your arm. It may come with chest discomfort, breathlessness, sweating, nausea, or arm or jaw pain. If you have any of these, go to the nearest emergency department immediately.

Why does my left upper back hurt when I take a deep breath?

The most common reason is a sprained rib joint or strained muscle between the ribs, especially after coughing, lifting or twisting. Pleurisy and chest infections also cause pain with breathing, usually with fever or cough. Sudden sharp pain with breathlessness needs emergency care.

How long does a rhomboid or trapezius strain take to heal?

A mild strain usually eases within a few days to two weeks with heat, gentle movement and posture changes. Pain lasting longer, or returning often, usually has a driver such as desk set-up, weak shoulder blade muscles or poor sleep, and benefits from a guided programme.

Do I need an X-ray or MRI for left upper back pain?

Most muscle and rib joint pain does not need a scan. Imaging helps after a fall, with osteoporosis, fever, weight loss, night pain or nerve symptoms.

Where can I get upper back pain left side treatment in Bengaluru?

Dr Heal Pain Cure Hospital examines and treats upper back pain at its HSR Layout and Banashankari branches, with in-house laboratory and radiology. Both are open 24 hours, and patients come to us from all over Karnataka.

This article is for general information and is not a substitute for a medical consultation. Please see a doctor for advice about your own symptoms. If you think you may be having a heart attack, go to the nearest emergency department immediately.