Cause of chronic nausea, pain and pressure under left ribcage and sternum

[StorminD]

Over the 4th of July holiday last year, I had a two day bout of diarrhea and GI pain. Since that time, I've had constant bloating and pain under my left ribcage, constant nausea, pain in my sternum, and early fullness/loss of appetite. I have a history of GERD but this is much worse. I've had a negative endoscopy and CT and all normal blood work. My GI doc is at a loss and recently scheduled a HIDA scan. My only non GI symptom is an inability to tolerate heat/hot temps. The pressure increases when I got hot and I get faint. Any input would be appreciated.