I have diverticulosis in the sigmoid colon, and atranal gastritis, I also have severe constant right upper quadrant pain but CT scan showed nothing?

Gallbladder? Might be worth checking out your gallbladder-- ultrasound is a better study for gallstones, and if there aren't any, then you may need a cck-hida scan to evaluate gallbladder function. Even without stones, if the function is abnormal you can have similar symptoms- right upper quadrant pain, radiation to shoulder, fatty food intolerance, flatulence etc.