Some physiotherapists treat frozen shoulder with a mix of exercises and short sessions with an ultra sound massage machine. Others use exercises only. If you are conscientious with the exercise routines, both work. I read somewhere that if you don't treat it at all and put up with the pain and stiffness, it goes away by itself after a year or so. If so, it is probably because your work or life-style forces you to keep the limb moving. Beware quacks though when seeking treatment. I know somebody in Switzerland who got frozen shoulder in the wake of arm surgery after falling off a ladder. The recommended treatment was more expensive than the original arm operations, and involved full body scans.   My advice is stick to the exercises. Given time, they work.