For most people, the colonoscopy itself is not too painful. They will sedate you so that it isn't too uncomfortable. However, the prep for the colonoscopy is miserable. You need to clean out completely so you are not allowed to eat the day before and the day of the procedure, you can only drink clear liquids the day before the procedure, you can have nothing (not even water) the day of the procedure. The doctors give you strong meds so that you will have very liquidly diarrhea until it looks more like urine than stool. These meds can made you hurt a lot.
For me, I had a colonoscopy when I was 15. The prep was horrible because I couldn't stop vomiting and the medicines made me cramp. However, I had general anesthesia for the procedure (you are completely asleep) because I am young so I couldn't feel anything.
Is doing a colonoscopy very painful? How does it feel ?
You should have a colonoscopy. If you have been having problems for 4-5 years, and medicines have not helped, your doctor should have advised you to get a colonoscopy a long time ago.