Re: Pelvic soreness
Have you done a self testicular exam? Do one of those. Look it up on the net if you need to know how to do one.
Climaxing at least once a week is important for keeping everything "cleaned out" down there. If you are sexually active and ejaculating once or twice a week, you are fine. The leakage you had was probably just left over semen, since you don't ejaculate often.
If these symptoms continue, you probably will need to break down and see a doctor. If you are in college, you can go to the student health center. If not, you can look for a sliding scale clinic in your area that will treat you for free.
Has there been anything else symptom wise? When does this pain occur? After bowel movements/after eating/when you are hungry? Any nausea/vomiting/diarrhea?