Small aches and pains in the left arm are often a normal part of aging. However, sudden or unusual left arm pain could be a sign of a more serious medical problem. It might be a symptom of an injury that needs treating or, in the worst case, the effect of a heart attack.

Being aware of the potential causes and characteristics of left arm pain can help a person recognize what the body is reacting to and determine when it is necessary to seek medical attention.

In this article, we explain the possible causes of left arm pain. For each of these causes, we describe the other symptoms that can help a person identify the underlying issue.

Heart attack

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Left arm pain could be a symptom of heart attack when it occurs alongside other symptoms.
A heart attack occurs when a portion of the heart muscle sustains damage or completely stops functioning due to a lack of oxygen.

Most heart attacks happen as a result of narrowing in the coronary arteries. The arteries become narrow due to a buildup of plaque. If a piece of plaque breaks loose from the artery wall, it can cut off the flow of oxygen-rich blood to the heart, which may cause a heart attack.

Left arm pain is one of the most common symptoms of a heart attack. The nerves that branch from the heart and those coming from the arm send signals to the same brain cells. As a result, the brain cannot isolate the source of the pain.

This phenomenon, called referred pain, explains why a person experiencing a heart attack might feel arm pain without having chest pain.

The American Heart Association advise calling 911 if sudden left arm pain gets worse over a few minutes or occurs alongside any of the following symptoms:

discomfort at the center of the chest that lasts longer than a few minutes or goes away and then returns
pain, numbness, or unusual discomfort in the back, neck, jaw, or lower abdomen
breathlessness with or without chest pain
indigestion
nausea or vomiting
lightheadedness
sudden cold sweats or flushing
Chest discomfort is the most common symptom of heart attacks in men and women. It takes the form of pressure, tightness, fullness, burning, or gradually building pain.

However, women are also more likely than men to experience other symptoms when having a heart attack, such as shortness of breath and nausea. They may incorrectly attribute these symptoms to a virus, indigestion, or stress.

If a person experiences any sudden combination of nausea, vomiting, shortness of breath, or pain in the lower abdomen, back, or jaw, they should seek medical attention immediately.

Angina
People experiencing angina feel discomfort or pain as a result of the heart getting less oxygen than it needs. Along with left arm pain, symptoms might occur in the shoulders, neck, back, or jaw. Angina may also feel like indigestion.

Angina is not a heart attack. However, it is a sign of a heart problem. Clogged or narrowed coronary arteries are often the cause of angina.

There are two main types of this condition:

Stable angina

Stable angina is a predictable and manageable type of angina. It occurs consistently for at least 2 months and only during times of physical effort or emotional stress.

These circumstances put extra strain on the heart, meaning that it needs more oxygen than the narrowed arteries allow. Rest can help a person treat stable angina. If necessary, a doctor may prescribe an artery-relaxing medication called nitroglycerin.

Unstable angina

This type of angina is more unpredictable and dangerous. It can occur even when a person is resting, meaning that the heart consistently does not get enough oxygen.

Unstable angina indicates that a person is at risk of a heart attack. A medical professional should evaluate people with unstable angina in an emergency room.

Skeletomuscular injury

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Pain can occur in the left arm due to injury of the muscle tissue or bone.
Left arm pain is probably not a result of heart problems if it has the following characteristics:

The pain has a “stabbing” quality and lasts only a few seconds at a time.
Movement or touch causes pain.
The pain only occurs across a small area of the arm.
The discomfort persists without other symptoms for hours or days.
Instead, the discomfort could be a symptom of injury to the bone or tissue in the arm, shoulder, or elbow.

However, even with a good understanding of these possible skeletomuscular conditions, it can be difficult to tell whether left arm pain is occurring due to injury or a heart attack. Certain risk factors for both, such as age and physical activities, also overlap.

For these reasons, it is important not to try to self-diagnose an injury or rule out a heart problem without medical assistance.

Common skeletomuscular conditions that might cause arm pain include the following:

Bursitis

A bursa is a fluid-filled sac that acts as a cushion between a bone and its surrounding soft tissue. Bursitis is inflammation of the bursa.

Left arm pain may be a symptom of shoulder bursitis, which usually results from overusing this joint. If the bursa sustains direct trauma or becomes infected, this may also contribute to left arm pain.

Tendonitis

Tendonitis is the inflammation of the connective tissue between muscle and bone. Tendonitis often develops due to repetitive joint use. For this reason, tennis players, swimmers, and musicians often get tendonitis.

Tendonitis in the shoulder or elbow could be the source of left arm pain.

Rotator cuff tear

The rotator cuff is a group of muscles and tendons that hold the shoulder in its socket and help a person rotate the arm and lift objects.

A tear in the soft tissue of the rotator cuff can be very painful. It typically results from shoulder overuse or direct trauma. Aging also causes degeneration of the shoulder tissue, which can increase the risk of a tear.

Here, learn more about a torn rotator cuff.

Herniated disk

When one of the cushioning disks between the vertebrae of the spine ruptures, it juts out between the spinal bones and pushes against the surrounding nerves.

If the disk pushes against nerves that serve the arm, a person may feel arm pain, numbness, or weakness. These symptoms might resemble those of a heart attack, but the cause is different.

A common cause of disk herniation is heavy or repetitive lifting.