This is characteristic of AS. The problem is that when we are sleeping, we are essentially not moving (much). With AS, when we don't move, we become very stiff. Lower back pain in the morning, and I would imagine you feel very stiff and have difficulty moving for a bit, is the result of this. DragonSlayer's very technical and gut-related explanation aside, you are very normal when it comes to AS.
How long before the stiffness passes?
White light and love,
