Had csection 18 m ago, now have narrow stools, constipation, diarrhea, abd pain getting worse have colonoscopy aptment, should i be worried?

Unlikely: Just so you know, your profile says you are a male (and we know they can't have cesareans!). If you are 28, then colon cancer is very unlikely, though not unheard of, i'm glad you're getting a colonoscopy. I don't think your bowel issues are related to cesarean. There could be scarring, but most women don't have bowel complications following cesarean. Trust your doctor will find out problem, .