I have been for a few months now having blood in my semen, i comes out most of the times red, after having sex with my partner it hurts to urinate and at the very begining i urinate blood, i went to the doctor and got tested for urinary tract infection, and i came out to be negative, the doctor said that it was comon for a person my age (24yrs old) to have this happen to them, but like i said its been over 4 months now, i have been with my partner for 2 yrs now, so no transmitted diseases, well that is my assumption since my partner is perfectly fine, also adding to this when i eyacualte it hurts as well. when i have no sexual relations i urinate fine, it doesnt hurt, i dont know whats going on. Im very worried, please help out.

Mike