Hey nudist smurf,
Hope I don't mess up your play by crossing the streams, but I was in the EXACT same situation as you a couple of years back. (One of the reasons I didn't buy OWC at the time) It was prostrate related, and while all the medical lingo and tests scared my mom, it ended up not being that bad and two years later my father is 100%. If it is prostrate related, it's fairly common and surgery usually solves it.
Good luck!