A few years ago I had similar, very very serious pains in my chest, so bad I was panicking like mad and thought I was going to snuff it. I phoned a very close doctor friend who came over to see me, and assured me it was not cardiac. He said there are a couple of key features missing, and no I'm not going to tell you what they are otherwise you'll get them ! I went to the library and borrowed a book on coping with pain, and learned a lot.
I was under *severe* stress at the time at work, a whole critical project depended on me, and in retrospect it seems so clear, but it didn't while it was happening.
Good luck, get checked out. The mind can do amazingly bad as well as good things to the body.