I'm 21. For over a few years I have had problems with indigestion. Most of the time, it affects me on the left side of my chest and bothers my left arm. (It does not hurt, but it does bother it) For the longest time, I thought it was indigestion. But with the recent health of my grandmother, I'm beginning to wonder if I might heart issues instead. I'm eating better for the most part and have lost a lot of weight. I have tried to talk to my mother about this, but push the issue aside, claiming it's my breathing pattern (I breathe through my mouth mostly due to my allergies) and that I'm too young to have any problems with my heart. Anyway, does this sound like something serious?