Sorry to hear about your injury.
I
had an old Dirt bike injury that I never got checked out, I just lived with it. Slowly, and because I am stubborn, I worked through it, although every now and the then I would get "the twinge"...
Then I got a Kayak, and started paddling...lots! Usually trying to keep up with Kevin aka "the kid" to try and get a bit of wisdom, or maybe even a left over fish or two!!
There have been days I have paddled for 12 hours, and could hardly move in the morning, but I can say my shoulder is back to 100%!!! In fact, although I can see huge advantages to the hobie peddle system, I love paddling for my shoulders!!
I hope for you your shoulder injury works out as well as mine did...
cowboybill