Is it normal for peeing to be painful right after having sex?

May be normal. The urethal opening is exposed surface. The urethra sits above the vagina with relatively small thickness layer of tissue between the two (i.e. Urethral channel and the vagina). Penetration of the vagina and associated trauma to the urethral opening during sexual activities may be experienced as pain, irritation and or inflammation. Some women may see blood associated with sex acts.