Why am I getting bad chest pain when i breathe in?
could it be something I ate? or what could it be?
You sound like a heavy smoker. That sound like it could be bad. I'd see a doctor if it stays for a few days. It could just be heart burn or something.
It could be stomach acid, or yes, a food allergy. If it is difficult to breathe, or your throat is swelling up at all, go to the ER!
Do you run a lot? (I can probably answer your question using comments)
That happens to me all the time. I think its fine