It sounds more like the baby is on your sciatic nerve. Here is a website, but with the thighs, but pain and back back it hits it right on the dot.
Typically the symptoms of sciatica in pregnancy include the following:
Pins and needles in the lower back or leg, possibly the affected foot.
Shooting or burning in the leg, buttock or lower back.
Pain in the lower back or back of the pelvis that may extend into the foot.
Numbness in the leg or feet.
It is usually the result of the baby putting pressure on the nerve, which you will mostly feel the back/buttocks area. Put heat presses on it, and Tylenol as directed, but there really isn't much you can do about it unless it is persistant, if it doesn't go away until your next appointment they may want to do steriod shots to relieve inflamation.