Romper, Romper, Romper.........
Rowing ?????? Where do I start.....
This forum has a great support feel to it, so in the absence of anybody else saying it I will be brave, here goes....
Stop Rowing !
Rowing crunches you up into a ball, which is really bad for blood pressure, the back and the .... wait for it.... shoulders, and is even known to cause stroke in those not used to it.
Your bike is lovely, we would all agree with that, but the posture you have is really bad for the lower back, arms and shoulders.
As your medical advisor
may I suggest that you stop the rowing for at least 3 months. It will take that long for inflammation to reduce. If the shoulder problems go away, then give up rowing. Sadly all forms of sport have some bad effect on the body.
Taking a reality check, I think if you still have shoulder problems come Spring, you will need to reconsider your bike. Sports bikes damage arms, necks , and lower backs, cruisers that are not altered only have one problem in that the footrests are often way too far forward, straining lower back and arms/shoulders. A conventional bike will cosset the body, think of something like the BMW R 1200 GS. If you can ride it when standing up on the pegs then it will give you a low stress posture when sat. I have a standard VN900 Classic , the only mod I would like is bring the footrests rearward, the opposite of fashion, to give my lower back more support and allow me to naturally lean slightly toward the handlebar rather than hang off it.
If you cannot ride your bike with completely relaxed arms, then it will always strain something. Its that old triumph of style over practicality.
Seriously though, give your shoulders a rest from the rowing punshment, and take up walking instead. Google Andrew Marr, he is a young popular UK TV commentator who nearly lost his life due to a rowing machine.
Good luck with it. This post has been written with all good intentions, so I hope it is taken that way.