This is my first post and I'm glad to officially be part of the forum!
Recently I got back into biking after taking years off from riding. I have been mostly riding on flat land, commuting to and from class at my university. I am in average to good condition and have noticed the top muscles in my legs (not sure the technical term) closest to my groin to be very tight after riding.
Is this because I am building muscles again? I am not over-working myself, but I do try to push past the burn.
Cramps, especially in the thigh, are horribly painful things that leave you gasping for breath, cause tears to come to your eyes, and make it incredibly difficult to pedal, walk, or even get off the bicycle.
What you're describing could be ... the bicycle doesn't fit you quite right? Or maybe it is just the process of building muscle?
Just do be sure to drink water before, or during your rides.