It sounds alot like u falling off bike hun, but best getting anything like that checked out to be on the safe side. Have you got anyone in family you could speak to about this and take you to doctors to have it checked. 

I know it can be an embarrassing subject for a young man but it will put your mind at ease to get everything checked out and put your mind at ease.

This could be due to the accident, or it could be an infection that needs antibiotic. Either way, you do need to get yourself checked out by a doctor.  It will almost certainly be nothing too serious, but you'll continue to be in pain until you get proper medical help. 

Note that you don't have to be having sex to get an infection in this area. Many times it just pops up out of nowhere for no reason.