After i masturbate, i can feel my penis throbbing and it hurts a bit. is this normal?

To some degree.: During an erection, the outflow of blood from the penile tissue is temporarily blocked. When blood starts flowing again, you might feel a throbbing sensation. It shouldn't hurt, however. If you can't identify anything you're doing during masturbation that could cause pain afterwards, you should consult a physician. Please don't let self-consciousness prevent you from doing so.

Yes: Does it hurt or just feels different to touch. In either case it is not abnormal.