Just some thoughts here...
Do you have diarrhea or abdominal spasms?
The area you're talking about (just to the left of the right hip bone) could involve the appendix or the ilio secal valve (sorry, don't know how to spell that). That's the juncture between the small intestine and the large one. I don't think the colonoscopy would show if that valve is partially stuck open. I knew a chiropractor years ago and his was stuck open, gurgling, but he had diarrhea too. My aunt was able to close it for him with a particular type of hands-on energy treatment, something like Reiki.