Freaking out I'm having a heart attack?

Nothing about rib and underarm pain says cardiac and the hospital already ruled out cardiac causes.

Take some ibuprofen or naproxen and get some rest.

Let me ask you this: when you MOVE, does it affect the pain under your arm?? Because that would be indicative of a muscle pull/tear.

Since you got an EKG and it was normal, please rest assured that it was not a heart attack. However, that doesn't mean that there isn't a chance it isn't something that needs to be followed up on (btw, you didn't write your age/sex, which is very relevant). Pre-menopausal women and men under the age of 40s rarely suffer from heart attacks, unless they're BORN with a heart defect - detected or not. I would wait a few days (did they give you anything for the pain?) and then go to your regular doctor. A mild anti-anxiety drug could really help, so you might want to consider going sooner, but again, based on whether the pain gets worse when you move, my guess would be that it's muscle related, since they cleared you from the ER. Good luck and try not to worry...

Get a angiogram and look for blockages .

Better yet , go to a good doctor and get a check p.