Put a towel in bottom of bathtub, place oven rack with pizza stone on the towel and cover with hot water. Allow to soak for a while or until you can remove the stone.

There may have been sugar or other kinds of drips on the oven racks that fused the pizza stone to it. Water will soften the drips allowing the stone to release.

Be sure and let pizza stone dry completely before using.

Thanks, krissie. I will try this.

I recently read a tip somewhere that recommended using fine grit sandpaper on pizza stones to remove baked on stuff and oil residue build up. Your stone may benefit from a quick sanding once you get it unstuck to rejuvenate the surface.