Stomach problems

So, every day I get a really bad stomachache. It's been going on for months. It lasts a few minutes at a time. The last time this happened I had this thing where my stomach acid was burning my stomach, so the doctor had me take Zantac. They aren't as bad as they were before, but they're still painful and they're still annoying. It is a possibility I have anxiety, if that means anything. I heard the could be part of it. What could it mean? Thanks ^^