Welcome back, sportsfan!
Sounds like you need an abdominal ultrasound and HIDA scan. Gallbladder problems very frequently cause URQ pain that radiates to the back, nausea, feverishness, etc. Did you ever have these done before?
If you had abnormalities on several tests in the past, even if your enteroclysis (with the tube down the nose) was negative, you should definitely get a second opinion. Even if it's IBS, a GI should be able to follow you; that's what they are there for!
Co-moderator - IBS Forum