I have had a frozen shoulder on both sides.
First time: Right shoulder. 10 years ago. Lots of Physical Therapy that didn't help and was TOTALLY, TOTALLY painful!!! Finally had surgery and a small round of physical therapy and no problems with it since.
Second time: Left shoulder. 3 years ago. Didn't want to go to the doctor cuz I didn't want surgery, so just did stretching exercises against a doorjam for a whole year and all of a sudden, one day it dawned on me - - my shoulder didn't hurt any more and wasn't restricted. Hallelujah!!