Another thing that helps "post ride" is desitin - the stuff you put on baby's butts. It is a little numbing and has stuff to help with the chafing.

You'll toughen up after awhile, sister!

Congrats on starting out. Keep your legs spinning (don't push big heavy gears) until you build up some muscle, tendon & ligament strength. Even after that, pushing big heavy gears isn't a good thing.