I inserted 4 tablets of misoprostol into my vagina, after 2 hours i had to pee and my abdomen was hurting badly. after i peed the pain stopped. is it possible the pills fell out?

It's possible but unlikely. Unless you didn't place them very far up, you had to strain to urinate, or if you had significant pelvic relaxation from prior childbirth, they should stay in place. Even in those other situations it would be difficult to expel them.

Your pain was probably due to holding urine and if you placed the pills deep enough they did not fallout