I'm following this with interest and want to share a personal experience.
Having had a frozen Left shoulder that lasted almost 18 months before it went away (no treatment), only to then find that my Right shoulder started to go the same way, having avoided medication first time around and after consulting with Google, I started taking Ibuprofen and it became ok, not perfect but not as bad as my previous experience of frozen shoulder. I continued taking Ibuprofen as more a preventative measure and did so for a number of years until I had a fairly bad accident.
Now that bad accident broke a few posterior ribs that left me with only one way to lay down in bed (couldn't sit back in a chair either) and that was I had to sleep propped by pillows with my body weight resting on my Right shoulder (and my right ear, but thats a different story), because the broken ribs were behind my Left shoulder blade they were non-aligned and for quite some time were also non-union, so it took a long time of sleeping on my bad Right shoulder until eventually my broken Left posterior ribs formed union (but still non-aligned) and I was no longer required to sleep on my bad Right shoulder. Now the positive side was that suddenly (or at some point in those 3+ months of my Right shoulder taking the pressure of my bodyweight) my Right shoulder no longer has any frozen shoulder symptoms.
I'm generally not superstitious, but I'm touching a bit of wood as I type this.