Frozen shoulder 8 months before my dx was an early symptom. And 12 months of painful PT gave me full range of motion again.
This past year I noticed my elbow tightening and getting increasingly painful. It dawned on me that this was probably how the frozen shoulder had begun. So I notified my neuro & then I started doing the PT exercises & stretching & heat treatments on myself and I managed to "cure myself" over a period of 6 months.
I went back to my PT after I got my PD dx - to let him know the cause of my frozen shoulder just in case some other undiagnosed people w/pd came in with the same symptoms. The PT called me one day to say another such person w/ frozen shoulder did indeed have PD.