For about a year or two, I've been having chest pains. It's directly in the center of my chest and the best way I can describe it is the plates of the earth's crust, how they press together, only it feels like that in my chest. I've tried ignoring it, and that usually works. I've tried taking tylenol and other things like that. It has no effect. The pains are random and can stop for weeks to a month at a time. What could this be?