Does left arm pain always mean a heart attack?
No. Left arm pain can result from strain, tendon problems, injury or nerve disease, but may accompany a heart attack, particularly with chest pressure, breathlessness, sweating or nausea. Location alone cannot confirm the cause or rule out the heart.
Details
When to call emergency services
Call immediately for sudden pain with heart-related symptoms, fainting or clear deterioration, and do not drive yourself. Sudden arm weakness with facial droop or speech difficulty is also an emergency because of possible stroke.
Describe details instead of self-diagnosing
Report onset, exertion, movement, injury, numbness and swelling. Assessment may include the arm, neck and circulation, with ECG or other tests if a cardiac cause is suspected.
If minor strain seems likely
Reduce the provoking activity without ignoring persistent or worsening pain. Deformity after injury, severe pain with limited movement, or redness and fever needs prompt care. Pain relief after a medicine cannot rule out a heart attack.
Related reading: What causes left shoulder pain, and when is it an emergency?.