40s male with IBS, with nagging EGR pain 6days post biopsy-free colonoscopy. No fever, blood, some bm. What non-perforation complications are likely?

IBS may be nervous. Many patients with IBS have it because of automatic brain dysfunction. The bowel has it own nervous system that receives signals from the lower brain, enabling it to function properly. I would guess that your diet is poor because that is the commonest way to affect the control mechanisms. Try shaping up your diet and get rid of all the sugar.