i do that also got so bad at one time when i was married i asked my ob/gyn and he tols me it was just muscle spasms.
When you orgasm, your uterus contracts along with your pelvic floor muscles (meant for helping sperm get to the final destination!)
The pain that you're feeling and the 'muscle spasms' that the pp's doctor was referring to is more than likely just the uterus contracting.
well it kinda sucks lol
anything i can do to prevent/relieve the contracting so it's not painful?