He can't Move if he sleeps on his stomach, so he's been sleeping on his back when he's able to sleep. It started out at the top of his tailbone, but has moved to the perineal area. He says that it's sharp shooting throbbing pains like a cavity. Last night he started getting numb in his ring and pinkie fingers on both sides. He had an MRI that showed nothing a few weeks ago, but the numbness scares me.