Just wanted to say I'm in the same boat and I sympathize.
After taking a long course of antibiotics last year for a sinus infection, I've suffered from bloating, belching and shortness of breath. PPIs didn't help. I've tried everything, including probiotics and digestive enzymes, to no avail. I can hardly go out in public because of all the belching. Somebody on this board suggested that esophageal spasms might be caused by a lack of magnesium, so I"m trying magnesium supplements now. I'll let you know how it goes.