I am an active 73 year old. At 5:00am I was awake to pee and felt a new pain deep in the muscle that runs between my nipple and right armpit. it was relatively dull and not quite debilitating. It lasted roughly a half hour. I did some deep breathing (my wife s suggestion) and that seemed to help a little. I slept-in, awaking at 9:00 am with no ill effects. Could have been my first heart attach? I do intend to see my internist Monday.