What Causes Burning Sensation In Chest?

Hi my name is stag for the past couple of weeks Ive been having a weird dull burning sensation in my chest when i breathe. I have been worried about it cause normally after a few days of feeling sick I usually go back to feeling normal. I went to the ER twice for some chest pains that I was having near my heart area once to urgent care the other at a local hospital here in florida was checked out after some blood work and x rays were done they said that it was not heart related but to follow up with another doctor. I was feeling nauseous but that has gone was having mild headaches but thats gone the only thing that remains is this weird burnin sensation in my chest please help.....also i started feeling much better after i had this infected tooth pulled out unsure if its related