Do you mean the immediate day, or few days, after the colonoscopy? Most of mine were no problem, but a couple of times turned out as you describe. During colonoscopy, the doc has to blow air into a particular areas of bowel to navigate, examine it better and/or take biopsies. They usually get all the excess air out before you wake up, but sometimes they just don't get it all and yeah, it HURTS!
Living in the Republic of Texas minus a gallbladder, appendix, uterus, and 18" of colon; but living with my wonderful husband, 2 dogs, 1 cockatiel, and 2 gold fish.