During the last few months, I've have had these flare ups where it will feel like a stabbing pain in and behind my left boob. Breathing or moving makes it worse, but it doesn't stay long and it does it randomly. Anyone else have these or know what it could be? I've googled and it said acid reflux and gas pains can cause this and I have super bad GERD so that would make sense. It's just kinda scary to me and I have never had a mammogram.