I know of a particular type of neoprene shoulder brace that is designed to treat general stiffness in addition to pain. It's made by a company called FLA Orthopedics. I don't know for certain that it will help, but I suppose it can't hurt to try.

In the event you decide to give it a shot, the following is the one I'm familiar with and referenced in the above paragraph: http://www.eganmedical.com/Neoprene-Shoulder-Support-p/orbs-16-500.htm