@kmeikle1, Excerpt from article below -- "Symptoms may include muscle pain (myalgia) and stiffness in the neck, shoulders, upper arms, lower back, hips, and/or thighs."

National Organization for Rare Disorders (NORD) - Polymyalgia Rheumatica:
-- https://rarediseases.org/rare-diseases/polymyalgia-rheumatica/

I am also tapering down from 15 mg 18 months ago to 1 mg present, and my symptoms have been exactly same as yours. Between waist and knees, and left thigh definitely more troublesome.

As to bilateral pain, I do think it is almost always bilateral. But NOT always. Certainly one can get pain worse on one side or the other, but usually there is some pain bilaterally. It is hard to differentiate at times from overuse injuries as all of us struggle to do what we can and sometimes overdo it. While on Pred, injuries take longer to heal, so it’s hard to know if it is caused by PMR or is something else indirectly related to work stress or exercise.
About tapering, everyone is different but more people report success with a very slow taper, thereby avoiding flares. When we start, we don’t know our threshold so tapering can go rather quickly. In other words, if you are newly diagnosed, your doctor may prescribe 20mg a day to start, even though you really could get by on 7 (which of course you and your doctor can’t know). So you do well, cut to 15, and do well, etc., down to 7. When you cut from 7 to 6, you may flare, so you have to go back to 7 and slow the taper. (Actually many people do have a problem tapering when in the range of 6-8 mg because that is the level of cortisol normally produced by functioning adrenal glands. They “shut down” when you take more Pred, and hopefully “awake” when you start dipping below 7 mg).
John is right that many of us can be dependent upon Pred for years, or even for life. Everyone is different and we can only speak in terms of generalities.