CRPS can most definitely spread! Mine started in my right wrist and hand and has now spread to both arms, shoulders, and left hand. Most of my pain centers around my right elbow and back of my right arm. As far as I understand there is a branching off of the nerves at those locations so, the misfiring can be more severe there. I use a heating pad at night wrapped in a silky pillow case to help ( sort of ) relax the muscles and stimulate the nerves to "relax" as well.