Pain Under Left Shoulder Blade: Causes and When to Worry

Pain under the left shoulder blade usually comes from the muscles around the blade, the small joints where the ribs meet the spine, or the lower neck. That pain tends to change when you move, twist or press on the spot. Less often, it comes from the heart, lungs, main artery, pancreas or stomach. Those causes usually bring other signs: chest pressure, breathlessness, sweating, fever, or pain tied to meals. If any of those are with you now, read the next section first.

Where exactly it hurts narrows the likely causes. This page helps you narrow them down; it does not diagnose you. For pain on either side, shoulder blade pain by location covers each part of the blade.

First: the signs that skip the queue

Call your local emergency number now if

Chest pressure that spreads: pressure, squeezing or heaviness in the chest that spreads to the left arm, jaw, neck or between the shoulder blades.
Back pain with other body signs: upper back pain with breathlessness, a cold sweat, nausea or lightheadedness, even if the chest itself does not hurt.
Sudden tearing pain: severe tearing or ripping pain in the chest or between the shoulder blades that is at its worst from the first moment.
Sudden breathlessness: sharp chest or back pain that is worse on breathing in, with sudden breathlessness, a racing heart or coughing up blood.
After a blow to the left side: new left shoulder or shoulder blade pain after a fall or a hit to the left ribs or upper belly, especially with dizziness.

See a doctor today if

Sharp pain that eases leaning forward: chest or left shoulder pain that is worse lying flat or breathing in and easier sitting up and leaning forward.
Fever with pain on breathing: a cough, fever or chills with sharp pain when you breathe in.
Upper belly pain going through to the back: with nausea or vomiting. If the pain is severe, treat it as an emergency.
A swollen, tender calf: with any chest or upper back pain, especially after surgery or a long flight or drive.
A band of burning pain: around one side of the chest or back, with a rash appearing in the same band.

Women, people with diabetes and older adults are more likely to have a heart attack without crushing chest pain. Upper back pain, breathlessness, unusual tiredness or nausea may be the main signs. If you are unsure, get checked.

Heart and lung causes: what tends to set them apart

Heart, lung and artery problems rarely change when you lift your arm, turn your trunk or press on the sore spot. They are linked to effort, breathing or lying down, and arrive with other symptoms.

Heart attack or angina: pressure or heaviness rather than a sharp point. Angina comes with exertion and settles within a few minutes of rest; new or changing angina needs a same-day check.
Pericarditis (inflammation of the sac around the heart): sharp pain, worse lying flat or breathing in, eased by leaning forward. It often follows a viral illness.
Pulmonary embolism (a clot in the lung): sudden breathlessness and sharp pain on breathing in. More likely after surgery, long travel or with a swollen leg.
Aortic dissection (a tear in the wall of the main artery): sudden, severe, tearing pain between the shoulder blades or in the chest. More likely with long-standing high blood pressure.
Pleurisy or a collapsed lung (pneumothorax): sharp pain on breathing in.

The guide to whether left shoulder pain is from the heart or the shoulder goes through these differences in detail.

Inner edge, between the blade and the spine

The most common spot. An ache or burning strip along the inner edge of the blade, sometimes with a tender knot. It builds through a long day at the desk, a long drive, or carrying a bag on the left.

Muscle strain or overload: in the rhomboids or middle trapezius. Tender to press, eases with movement and warmth, and often follows lifting or a heavy week at a screen.
Rib joint irritation: a sharp, pinpoint pain about an inch or two beside the spine that catches on a deep breath, a cough or a twist.
Pain from the lower neck: an ache along the inner edge that changes when you move your neck more than when you move your shoulder.

Top of the blade, toward the neck

A tight, aching band from the upper corner of the blade into the side of the neck, worse looking down at a phone or carrying a bag on the left.

Levator scapulae or upper trapezius strain: tender at the upper corner of the blade. Turning or tilting the head away from the sore side pulls on it.
A neck joint or nerve root: pain that starts in the neck and is worse looking up or turning toward the sore side. It may spread down the arm.

Deep under the blade

Pain that is hard to point to with one finger, felt beneath the blade rather than on it.

Referred pain from the lower neck: the discs, joints and nerve roots in the lower neck commonly send pain under the blade. A pinched nerve can start as a deep ache here before any arm pain or tingling appears.
A rib joint: deep pain that catches with a full breath or a twist and eases when you sit still.

Muscle and joint pain usually changes when you move or press on the spot. Pain that does neither, and arrives with other symptoms, needs a doctor.

Outer edge and back of the shoulder

Pain on the outer blade that spreads to the back of the shoulder often belongs to the shoulder joint. It is worse reaching behind you or across your body, or lying on the left.

Rotator cuff tendon pain: the infraspinatus, a cuff muscle, sits on the back of the blade. It aches at the back and side of the shoulder, worse overhead and at night.
The nerve to the back of the shoulder: a deep ache with weakness turning the arm outward, sometimes with visible thinning of the muscle on the blade.

Pancreas and stomach: rarer sources

Organs in the upper belly share nerve pathways with the mid back, so a problem there can be felt under the left blade. These causes are tied to eating, drinking or digestion rather than posture.

Pancreas (pancreatitis): upper belly pain that bores through to the back, often after eating or drinking alcohol, with nausea or vomiting. Sitting forward may ease it a little. Severe pain needs emergency care.
Slower pancreas problems: a gradual dull ache with unexplained weight loss, dark urine or yellow skin needs a doctor within days.
Stomach (a stomach ulcer): burning or gnawing upper belly pain linked to meals, sometimes felt in the back. Black, tarry stools or vomiting blood or material like coffee grounds needs emergency care.

Where else this could be coming from

The neck: shoulder blade pain that comes from the neck changes with neck movement. When arm pain, tingling or weakness join it, the pattern fits a pinched nerve in the neck better.
The upper back muscles: upper back strain usually follows a clear load and settles over days to a few weeks.
The ribs: rib joint pain is sharp, close to the spine and catches on breathing in or twisting.
Both sides at once: if the pain sits in the middle or crosses to the right, pain between the shoulder blades is the closer match.
The shoulder joint: rotator cuff tendinopathy causes pain on the outer back of the shoulder that is worse lifting the arm.

Still not sure

Get assessed by a doctor or physical therapist if the pain is not clearly easing after about one to two weeks, if it keeps waking you at night, or straight away if any sign from the first section appears. Constant pain that no position changes, with feeling unwell or weight loss, needs a doctor first.

Arrive with a few answers. Is it worse with movement, breathing, effort or meals? Does pressing on the spot reproduce it? Did it follow a strain, a new task or an illness?