I have to strain to poo?

Straining for BM: Most likely cause is constipation due to insufficient fiber & fluid in diet or due to pain medications that contain narcotics. Resolution takes a few days: use stool softener & increase dietary fiber (fruits & veggies)or fiber supplement along with plenty of fluid . Avoid laxatives as body needs more & more to work. If persists, see fp to check for other causes: polyps, mass, inflammation.