I went to bed last'night and I noticed a very light bruise on my chest just above and between my breasts, but this morning it is gone. During while I was trying to fall asleep there was a very sharp pain between my shoulder, bellow the armpit but above my breast. If I breathed too much it worsened, and if I slowed my breathing it still hurt. My heart felt like it was beating really, really slow and my whole chest felt heavy but the pain was only on my left side. I searched a little before coming here and the only thing that was close said I had an anxiety attack, I have never had one before.