G'day all, new to the site and saw this thread. I am just coming back from 7 months on the sidelines due to similar symptoms but in my left arm.
I was diagnosed with an adhesive capsulitis caused buy both rotator cuff muscles and the AC joint. I was also very stiff in my neck.
Even though the shoulder was the problem I suffered nearly no pain in the shoulder itself. I suffered sharp stabbing pains about 4 inches down from my shoulder on the outside of my arm.
None of this showed up too much on all my scans except for an MRI which showed some thickening of the tendons.
I was administered a cortisone injection into my rotator cuff followed a week later by a hydrodilitation. The shoulder improved somewhat but returned after about 9 weeks. I was referred to a shoulder surgeon and after noticing I lacked rotation in my arm he gave me a cortisone injection into my AC joint followed by another hydrodilitation. 6 weeks on my shoulder feels alot better. First time with no pain since October 2004. I still have weakness in my shoulder with my outward rotations but started gym to help strengthen. Also throwing a tennis ball against a wall while keeping my arm in an "L" shape straight up (technical term.. haha)
I'm not saying this is what you have... but I was certain something was wrong with my arm and was only convinced it wasn't until it went away after shoulder treatment.
If it isn't being resolved then seek a second and third opinion. I had a great team working for me and if one wasn't sure they referred me to someone who could help. I am still having physio once a week and in the gym 3 - 4 times a week and alot of stretching.
On a side note: I have just started with a new coach... TGM A-I here in Australia. Looking forward to making my mark now.