As you have found from walking, some exercise can leave you pain free. Both tai chi and qigong (chi gung) exercises can help immensely, as they have thousands of others. Because frozen shoulder and the pain it causes travels to your arm, fingers, neck and other parts of your body, these slow exercises work on the nervous system to first relax the periphery pain and then the main pain and begin to free up the shoulder. It's as though the knots in your muscles, tendons and ligaments begin to unravel. In Multnomah County lives an absolutely wonderful body therapist and chi gung (qigong) specialist named Fred Gordon, and the easiest way to get hold of him is through his email: firstname.lastname@example.org. He's exceptionally qualified.
I teach both systems in Burns, Oregon and learned from exceptional teachers, including Fred, and share information from tens of thousands others who have learned them and have cured frozen shoulder, tendonitis, carpel tunnel, back and neck pain, locked up jaws, arthritis, etc. They won't cure your shoulder tomorrow; but you will find that in the long run, you'll get rid of it pretty permanently. In my classes here, I have a woman 65 year-old woman recovering form a stroke, and her doctor told her she also had frozen shoulder and gave her pain pills. But slowly the shoulder loosens up, and so does her ability to move her elbow and fingers, let her whole arm hang down and swing a little. And with it the decrease in the pain pills she has to take. Cordially, Diane Rapaport, certified chi gung and tai chi instructor.