Hi Galen,
You might want to try two more exercises to help with your rehab, which I do every day in addition to the exercise above.
Start by holding the bow in more or less the same position you would hold it at full draw, except your string hand isn't on the string and stays by your side. Your bow arm is extended fully at 90 degrees to the side of your body, with the bow vertical and the string touching your forearm. Bending at the elbow, and keeping the bow vertical, slowly rotate the bow through 180 degrees until your bow hand touches your chest, and then back out to the starting position. Do 5 reps, then rest, and do three sets. Then do another 3 sets holding the bow in your other hand.
For the second exercise, draw a light bow to full draw and hold for several seconds. Keep your string hand at your anchor, and slowly let the bow down, using only your bow arm, bending at the elbow. The bow should stay vertical during this process. Still keeping your string hand at anchor, push the bow back out to the full draw position using only your bow arm. Repeat 4-5 times, then rest. Do three sets on each side if you can, but don't stress yourself.
Neither of these should hurt, although the second one will take some practice getting used to, even with a light bow, since you're using muscles you don't normally use when shooting the bow, which is really the purpose of these two exercises: to keep your body in balance.
Obviously, if you're doing these for rehab, you want to stop if they make the pain worse, and if you're working with a physical therapist, run them by him to see if he thinks they will help with your particular injury.