Is it normal to not have gas after colonoscopy? Had test 2 months ago and I do not recall passing gas afterward. I've read that most people pass a lot

Sure. While withdrawing the colonoscope from the cecum (first part of colon) to the rectum, the endoscopist will generally try to suction as much air as possible out of the colon, to reduce patient discomfort. Utilizing co2 gas also helps reduce postoperative gaseous distention.