Pain Under Left Shoulder Blade: Causes and Warning Signs

Pain under left shoulder blade is, most of the time, a matter of muscles, ribs or the way the arm and shoulder blade are used. Still, the left side sits close to the heart, so it helps to know the urgent signs first. This page starts there. Then it looks at why the left side in particular, and what to notice. Read it as background that works next to medical care. It cannot name the cause of your own pain.

Pain under left shoulder blade: the urgent signs first

Read this short list first, however mild your pain feels right now. Call emergency services, and do not drive yourself, if the pain comes with any of these, even if it started slowly or changes when you move:

• pressure, squeezing or heaviness in the chest
• breathlessness
• a cold sweat
• nausea, or a wave of faintness
• pain that spreads into the jaw, the neck or the arm
• coughing up blood
• sudden weakness or numbness

Pain under the left shoulder blade can occasionally come from the heart. Women and people with diabetes more often have quieter signs, and for a few people pain in the back is the only sign they notice. A sudden, sharp pain together with breathlessness can point to the lung and needs the same quick response. So does a sudden, severe tearing pain in the chest or back.

Most people with this pain do not have an emergency. These signs are simply the reason to ask for help first and ask questions later.

Why the left side, and how it differs from the right

On the right, a sore spot behind the shoulder blade makes doctors think of the gallbladder and liver. On the left, the organs near this area are the heart, the lung, the stomach, the pancreas and the spleen. They explain a small share of cases, but they are the ones that matter most to catch. Our page on behind right shoulder blade pain covers the right side.

For most people, though, the left side is about habit. Your two arms rarely do the same job. Think about your own day:

• The mouse hand. If your right hand drives the mouse, your left arm often props you up, rests on the desk edge or hangs without support. The shoulder blade then works to hold the weight of the arm.
• The phone. A phone held against the left ear, or read in the left hand, tilts the head and lifts that shoulder for long stretches.
• Driving. In many cars the left arm sits on a door, a window ledge or a wheel, with the shoulder slightly raised for a long time.
• Carrying. A bag, a child or a laptop case on the left shoulder keeps the same muscles holding on all day.
• A left handed life. If you are left handed, the reverse may hold. The left arm reaches and works, and the muscles around the blade grow tired from doing more.

None of this is a failing on your part. One arm has simply kept the same job for years. The Feldypedia guide to neck and shoulder tension explains how this kind of holding builds up.

The rib that sits under the blade

Under the shoulder blade lie several ribs. Each rib joins the spine at small joints, and those joints move a little with every breath and every turn. When the upper back is stiff, one of them can feel achy, catch when you breathe in deeply, or hurt when you twist. Many people describe it as a deep spot that they cannot quite reach.

This is one reason the pain can seem to change with breathing. A rib joint or a muscle attached to it can complain when the rib moves. The lung and its lining can hurt with a breath too, so this clue alone does not show that a rib is the source. The shoulder blade itself is a flat bone with no fixed joint to the spine, so muscles do most of the holding. When those muscles tire, the area under it is where many people feel it. Pain in the middle of the back, the thoracic spine, is common in general: across studies of children, teenagers and adults, the share of people reporting it in a single year ranges from about 3.5% to almost 35% (Briggs et al., 2009). That figure covers the whole thoracic spine, not the left shoulder blade, and the wide gap shows how much the answer depends on who is counted.

What makes a muscle or rib cause more likely

Here is the key idea. Pain that changes when you move or press the spot often comes from muscle or rib, but that does not rule out the heart, the lung or another serious cause. Only a clinician can do that.

Three clues point that way:

• It changes with movement. Turning, reaching or shifting your arm makes it better or worse.
• It is tender to press. A fingertip or a tennis ball finds a sore, local spot.
• It follows an activity. It builds after a long drive, a day at the screen, a carry, or a night spent lying on the left arm.

Keep one caution in mind. These clues make a muscular cause more likely, not certain. Pain from the heart or lung can also change with position or breathing, and some people with a heart problem also find the area tender. So use the clues to understand your habits, never to decide that you are safe. If any urgent sign appears, it comes first.

Other causes a doctor may look for

Some causes lie outside the muscles, and your doctor is the right person to sort them out.

• The lung or its lining. Pain that sharpens with a deep breath or a cough, sometimes with fever. If breathlessness comes with it, call emergency services.
• The stomach or pancreas. Upper belly trouble can be felt through in the back, often tied to meals or nausea. If it is severe, or you vomit blood or pass black stools, go to an emergency department.
• The spleen. It lies beneath the lower left ribs. A problem there may be felt high on the left, in the back or the shoulder. After a blow to the left side, this pain with faintness needs emergency care.
• Shingles. Burning or tingling in a band around one side, often a few days before blisters appear. Early treatment can help, so see a doctor promptly.

You do not need to work out which one it is. Tell your doctor how the pain behaves, even when it seems muscular. Book a visit as well after a fall or a knock, or when the pain brings a fever, interrupts your sleep, or comes with weight loss that has no reason. For the wider picture, see our page on the causes of upper back pain, or read about upper back pain on the left.

What to try when pain under the left shoulder blade is muscular

If a clinician has no concern, small changes are a gentle place to begin.

• Change position every half hour or so. Give your left forearm a surface to lie on, so the shoulder is not holding its whole weight.
• Turn your whole chair toward the screen, rather than twisting your upper back.
• Swap the bag to the other side now and then, or wear it across the body.
• Take a warm shower, or rest a warm pack on the area, if that feels pleasant.
• Breathe slowly, and picture the rear of your left ribs gently making room.

In the Feldenkrais Method®, the blade, the ribs and the spine are one working system. If the ribs stay stiff, the blade may have to do extra, and the muscles around it may feel that. Slow movement with attention lets many people find where they were bracing without knowing it. When the ache climbs toward the neck, Feldenkrais for neck tension may suit you better. If you want a guide, Feldy has short audio lessons, with a free week to try them.

One thing to try, and to tell your clinician

If no urgent sign is present, sit or stand comfortably. Slowly slide your left shoulder blade a little way forward, as if reaching, then back toward the spine. Keep it small and easy, and stop before anything sharpens. Notice whether the pain changes as you do this: does it ease, grow, or stay exactly the same? This cannot tell you that the pain is safe. It is simply a useful detail for a clinician, so write it down and share it.

Common Questions about pain under the left shoulder blade (FAQ)

Can pain under the left shoulder blade be a heart problem?

Occasionally, yes. Heart pain is mostly felt in the chest, but it can show up in the upper back, and a few people feel it only there. If the pain comes with chest pressure, sweating, nausea, breathlessness or pain into the jaw or arm, call emergency services, even if it started slowly. Do not wait to see if it passes.

How can I tell if pain under my left shoulder blade is muscular?

You cannot be sure on your own. A muscular pain often changes when you move or feels tender when you press the spot, and it often follows a task, such as a long drive or a day at the screen. These clues make a muscle or rib cause more likely. They cannot rule out the heart, the lung or other causes, and only a clinician can do that. Pain that sharpens with a breath can come from the lung as well as a rib.

What is the difference between left and right shoulder blade pain?

Muscles and ribs work in the same way on both sides, so ordinary causes look alike. The difference is in the neighbours. The right side points toward the gallbladder and liver, while the left has the heart, the stomach, the pancreas and the spleen close by. Habits differ too, because the two arms usually do different jobs.

How long does muscular pain under the shoulder blade last?

Many people notice a strained muscle easing over several days to a few weeks, especially when the habit that loaded it changes. Pain that lasts longer, keeps coming back, wakes you at night or slowly grows should be looked at by a clinician.

How often should I move if the area under my left shoulder blade hurts?

Short and often tends to feel kinder than one long session. A minute or two every hour, to change position and sense your left arm, is plenty. Keep every movement comfortable, and pause at once if the pain sharpens or any warning sign appears.

When should I see a doctor about pain under my left shoulder blade?

Book a visit soon if the pain lasts more than a couple of weeks, returns again and again, follows a fall or a blow, comes with a fever, or travels around the ribs in a band. Also go if it is linked to meals or to a cough. Call emergency services for the urgent signs listed near the top of this page.

Can the stomach or pancreas cause pain under the left shoulder blade?

They can. Pain from the upper belly, such as an ulcer or an inflamed pancreas, is sometimes felt in the back. Clues include pain linked to eating, vomiting, or pain that bores through from the belly to the back. Severe pain like this needs an emergency department.