A rotator cuff tear, which occurs when one of the rotator cuff tendons becomes detached from the arm bone, is a common cause of deltoid muscle pain. A rotator cuff tear can limit your shoulder's ...

Pain in your left arm can be due to a number of causes, not just a heart attack. Other causes like a muscle sprain, pinched nerve, or angina could be at fault. Check your other symptoms to ...

These are made of thousands of vulnerable muscle fibers. Awkward movements or overexertion can tear some, or all, of them. If 5% of the fibers are torn, it pulls the muscle. You'll feel an ...