It could be gallstone pain? I just had mine out so I am pretty familiar with this stuff!! My symptoms were mostly heartburn, but I did have pain in my upper right side also. Try this... don't eat any fat for a couple of days and see if it goes away. That was how I knew for sure... eating any fat would really hurt (within 5 minutes of eating).
Your doctor should do an ultrasound to rule gallstones out...
Good luck!!
It could be your gallbladder. Even if you don't have gallstones. There are those of us who have had there gallbladders go bad without any gallstones. Ask for an U/S or Hida Scan..