Wow, that sounds awful! I am glad that you are able to come back to chess! Welcome back!
Acid Reflux vs. Chess

Try Prevacid. That's what I'm on (generic version, though) and it keeps my acid reflux in check. Though mine wasn't caused by chess. Probably a combination of shift work and stressful job, though since I quit that it hasn't gone away so probably has a hereditary factor since my mom has the same problem.

I don't know about reflux in the esophagus, but I can tell you this from first hand experience. Too much sitting at chess play does cause hemmoroids. I don't think I spelled that right (English is not my native tongue). Roids...that's what they are. Especially if you like to eat, play a lot of chess and strain while calculating.
Also, never lean forward while doing these things. It only ascerbates (I think that's the spelling) the roiding process.

I had a friend with hemorroids. He could hardly sit down, and it was always bothering him. I could tell this the last time we played chess, when he appeared to be on edge. It affected his play, and after he hung his queen which I easily captured, he kocked the pieces away from the board and stormed off. This was the first time I ever experienced anyone with 'roid rage.
For years I had to relinquish my addiction to chess due to serious health concerns the least of which was acid reflux. Because my profession requires sumptuous oratory skills that place me under tremendous pressure combined with horrendous stress, I often overlooked my own personal wellness and the results; a damaged esophagus caused by regular regurgitation. I used to rely on Tums, Prevacid, Maalox, Rolaids, Mylanta, Zantac and others before my gastroenterologist suggested I set aside chess. “It cannot be done!” I roared in defiance. My bombast was futile because I knew deep down that he was right - it was either chess or acid reflux; the latter ultimately victorious. After a five year sabbatical, and dropping ninety-five pounds, I once again have returned to my passion, but not at a price.