Hello @rayabw, Welcome to Connect. You ask a good question. Have you discussed it with your doctor? I think it can mean something other than your PMR as a cause but then I'm not a doctor and have no medical training. Here's some information that may explain it for you.

Differential diagnosis of elevated erythrocyte sedimentation rate and C-reactive protein levels: a rheumatology perspective
-- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5047224/

You mentioned having PMR for almost 5 years and now being on a 3 mg maintenance dosage. Has your doctor ever discussed tapering off of prednisone as a goal? Normally you keep lowering the dosage until you are able to be off with no pain from the PMR.