Could this be heart or GERD???

I have currently been having pain under my left arm into my armpit. I'll get jaw pain and pain in my breast. Nothing unbearable. I have felt around and nothing is sore. It doesn't hurt to move my arm at all. I haven't done anything that would cause my arm to hurt. I'm freaking out that I might be having or getting ready to have a heart attack. I've also had lots of indigestion and feeling full sensation. I do have GERD and take 40mg of Propranolol for years. But, I do still get heartburn. This has been going on for 4 days now! I'm starting to really worry.