No Cerveza... No Trabajo
Join Date: Jun 2002
Location: Where's my beer?
Sounds like you may have pulled the muscles in the back of your neck. Happened to me playing HS football one game. The aftermath of your injury sounds alot like mine.
If it doesn't get better in a few days, go see a doctor.
Sometimes when someone flat benches, they will force their head into the bench during maximum effort. Forcing your head into the bench will place undue strain on the neck muscles.
My message board opinion is that this is what happened to you. But, like I wrote, if it doesn't get better, go see a doc.
In the meantime, take some Tylenol or Aleve 3-4 times a day for a few days. As far as bench technique, be concious of forcing your head into the bench during effort.