Hi Janm, you may have seen my few shoulder injury threads. I live in the south of Ireland, and found it really hard to finally get a solution to my problem. For basic general info, I did find the shoulderdoc.co.uk helpful as very few people here (doctors, physios, people) have much experience with tennis injuries. I had a gradual development of pain serving which one day after a long match, caused me to wake up and find it really hard to reach up or back. Long story short, I had no tear, just supraspinatus inflammation and impingement, had the SAD surgery, lots of rehab, and am back playing tennis (conservatively for the moment). I really had to push to get the MRI and had 4 cortisone injections (would not do that again). 18 months after the original injury the ortho specialist and I finally agreed the SAD was the best way out. In Ireland anyway, I really had to push to get the problem resolved, could be similar where you are, not sure. Having private insurance made a huge difference for me.
Best of luck getting the problem resolved.