What is the cause of having blood to my urine after sex? As I ve observed, if I m doing sitting position during our sex, then after that i feel to urinate and i also feel a massive pain because the blood blocks the urine passage, this is happening every morning then the next time I m going to urinate it is normal. It takes a week every morning or if i have an erection . The first time i have experience this problem last 1997, then i went to a doctor and i have an ultra sound, but the result is normal. Now from 1997 up to now 04 September 2010, I think 5 times I ve encountered this problem. Now I am 49 years old, is there any problem for my system ?