I'm not a "sir", but it sounds like you might have an infection in your prostate, or maybe a urinary tract infection.
The solution is to go to the doctor and get checked. This is nothing that you want to try to cure yourself, as you probably need certain antibiotics, and you don't want to take the wrong ones.
You need some testing done, so go to the doctor soon. Please don't wait too long - it will only get worse. And really, stop having sex. If you have an infection, you could be spreading it to your partner.