Right-sided pain under the armpit may be due to muscle strain ... back, arm, neck, or jaw. Pain radiating from the chest to one or both arms may be a warning sign of a heart attack.

Pain under your left breast doesn't necessarily mean ... You may also feel the same aching in your shoulder, arms, back, neck, and jaw. Heart attack symptoms can also include trouble breathing ...

This tightness, pain, or pressure may spread to your jaw, back, or neck. You may have all or just one or two of these symptoms, but if you experience any of these heart attack warning signs and ...