Looking for a little help.

I have been going through a lot of digestive problems for the past 3 months (acid reflux, slight pain and tightness in stomach-chest bone-back, burping, gas stuck in chest). It started after I had a tooth pulled and was put on Clindamyacin (after 3 day of taking it). I went to the ER they did an x-ray of my chest and did a lot of blood work, nothing was seen in the test. The following week I went to my regular doctor who took me off the Clindamyacin and he had me get an ultra-sound which showed nothing except for a little fat on my liver due to being over weight. He then sent me to a GI who preformed an EGD with many biopsy's. All of the biopsy's came back negative including the small nodule found in my stomach. He thought I may have eosinophilic esophagitis but with the biopsy not showing anything now I have no idea. He has me on Prilosec (2- 40mg per day for 60 days) I am still in the first 30 days, and it has worked pretty well for most of the problems. The one thing that is still bothering me is that my stomach tightens up often, no pain, just tightness. So for now I guess I am being treated for GERD and possible eosinophilic esophagitis. I will not see him again until the first of January. Has anyone else on here gone through anything similar and if so what did they finally find wrong? I do find that eating a GERD friendly diet helps. The not knowing for sure what is going on is driving me crazy. Thanks for your help on this.

The tightening is more like muscle contractions without pain. Almost like doing a crunch.