As I went throughout my day, my heart/chest and shoulder burned and felt like it was being stabbed. This happened twice. It also hurt my stomach. Right I took the first breath and felt the burning, my stomach felt terrible. It went away after a few minutes but came back about a half hour later. My friends told me it was heart burn, but I'm not sure. For the  rest of the day there has been a dull ache in my chest and occasionally my shoulder. My stomach ache has also been present.  I don't drink or smoke, and excersise regularly. Please help me figure out what this is!