Your butt is a muscle so i suppose its possible? Have you been to your post pardum check up? Thats some thing to definitely address.
Maybe try taking stool softeners so its easier for you to go, maybe it will help with cramping, as you won't have to push as hard.
The feeling is normal. Try to eat whole wheat & get a stool softener. If it gets worse contact the Dr
Ask your doctor, but you could have given yourselfa hemorrhoid durring birth.
You just sound extremely constipated. What is your diet like? Maybe take more fiber if it doesn't help ask your doc