Kate,

Are you sore from pressure or sore from chafing, that is, the shorts or the saddle rubbing you in the wrong places? If that's what it is, liberal use of some type of chamois creme should help stop the friction and make riding more comfortable. If it's pressure, I would agree with trying to tilt the saddle just a bit and see if you can find a more comfortable position. Sometimes moving the saddle a tiny bit for or aft can also put you in a more comfortable position. Good luck!