Hey, I've Been Feeling Like Something Is Moving Inside Mu

Hey, i've been feeling like something is moving inside mu buthole. It is very uncomfortable and it happens VERY often. Although when I have a bowel movement I do not see any worms of any sort. Is it possible for them not to come out? Also, I am experiencing when I have a bowel movement it is like it gets stuck and is very painful to come out, and it"s been going on for 3 weeks now. Is it poasible to have constipation for that long? And, after a bowel movement I feel as if didn't finish emptying the bowel, also expoernecing lower adomial pain, lower back pain, and loada of nausua.