I Am A Little Concerned About A Dull Ache In

I am a little concerned about a dull ache in my left chest behind my breast. I am under a tremendous amount of stress, today more than ever. I have a history of stress related chest pain in my right side of my chest just above my right breast but I have been thoroughly checked out with several stress tests and EKGs over the years and it was determined to be nothing but stress that I treat with a very low dose of xanax PRN. I very rarely take it. I have also been experiencing unusually high degrees of heartburn the last week or so.