Sounds less like a pulled muscle than something with the joint... pushing a painful joint usually is not a good idea - just leads to more problems - especially if riding is very painful.
A little rest now can head off a *lot* of time off later - so put some compression on it, keep up the ice and nsaids and give it a few days off. If it doesn't get better seek some professional help.
I can feel your pain - I haven't been able to race all month and will miss my favorite because of a problem with my knee/ankle - and mine is because of being hit by a car 2 years ago..... these things can linger if you don't take care of them.