With my constant "heartburn" I started on Zantac. Worked for a while, then didn't. Next went to Prilosec. Same thing. Next tried Protonix. Same thing. Next came Prevacid. That seemed to make things worse for me. Now I'm on Nexium 40mg 2xday. I have been diagnosed with Erosive Acid Reflux Disease. My gastro suspects my Crohn's Disease is to blame for this. When I flare up things back up inside me. Travel too slow. Therefore my stomach keeps making acid to rid itself of the contents. This constant acid machine has eroded the beginning of the lining of my esophagus and small intestine. So far the Nexium is doing the trick. However..... when I begin a Crohn's flare up, the burning begins.
This vicious cycle has been going on for about 18 years or so. I had an upper GI and it showed the problem with the acid reflux. The muscle that keeps the acid from the stomach from backing up into my esophagus isn't doing it's job very well. I also had an endoscopy and it showed the erosion. Maybe more tests are needed for you. Maybe a change of medications. We all respond differently to meds. I laugh when I see the commercials for prescription drugs. They promise us the world but never tell us about the times they do no good or make things worse. Keep working with your doctor. Don't give up! If we don't keep pushing, the doctors won't keep trying!!
Good Luck! I know the pain you're feeling and it can stop your day dead in it's tracks!