several years ago I was diagnosed as having PMR. I took Prednisone for a period of time but am not on any medication at this time. I do however, have inordinate stiffness and at night shortly after laying down and following exercise I predictably experience unusually painful cramps. Is this possibly a further symptom of PMR?
PMR can cause muscle and joint pain/stiffness but not commonly causing muscle cramps.it can be due to low potassium.  Chat Doctor.