Yes - see your doctor. Sounds like you might have "prostatitis" (check a few of the "strands" with that word - or even "ask Jeeves" - for more info).
One quick check, you could ***-ist with (please pardon the pun). At the doctor's you can anticipate a gloved prostate check. If the prostate seems at all squishy and not super-firm ~ then that's their first "clue". You can get a feeling (so to speak) yourself by digital insertion in the anus (lube recommended) and a probe towards your belly button.
Good Luck !!!
PS (as edit) ~ Odd as it might seem, just LAST NIGHT we were talking with the owner of a restaurant who had gone to a "teaching" hospital for his exam... His butt wound-up being examined by over a dozen trainees (and passers-by who could afford the small entry fees ?). Can you imagine ? I suppose the exam will be out on VHS / DVD within 6 weeks or so. Dadgum medical establishment !!!
[This message has been edited by Ben There (edited 10-04-2003).]