You should go to the doctor, just to be sure that it's nothing more than regular heartburn. But he'll probably tell you to buy something OTC for it anyway, unless you can get it cheaper with your insurance.
I don't have insurance right now....that's why I haven't been to the doctor for this or the other thing that I mentioned in another thread. I could go to the student health center but the doctors there aren't great...I may go anyway, though.
It could be "acid reflux". I have suffered from that. I agree with Lisa L, Pepcid AC Complete works good. Take it about 1/2 hr before meals. Another good one I found is is Maalox Max. These are chewable tablets to take anytime you have heartburn. When you have it don't lay down. Sit up straight.
If you think you are expecting, don't take any of these without consulting a doctor.