Doctors stumped after colonoscopy and CT

43 male.

Weighed 228 in March

Weight is now 184

Cramping - especially on lower right side for months on and off.
Regular appetite - eat the same as I have for years just drink way less alcohol. 2-3 a week vs 1-2 a day.

Anal pain and itching for over 6 years - especially at night. Checked and had colonoscopy 4 years ago and no issues - no hemorroids found.

Had colonoscopy weds and several polyps found : also had severe pain during procedure so they stopped and moved me to OR. Said nothing found

Had CT scans Fri and no issues found except for a spot on kidney which gets ultrasound tomorrow - tues.

On Fri I started having severe anal pain and went to ER where they said hey you have a fissure.

So - if nothing wrong w abdomen why do I get cramping and why does my butt hurt and itch?