Hi @michwest, I would like to add my welcome to Connect along with @hfoster. My first occurrence of PMR was when I was 64 and 54 does seem a little young. From what I've read it mostly occurs in adults over the age of 50 but there have been occurrences at younger ages.

"Can you get PMR in your 40s?
Since PMR can develop in mid 40s, a high index of suspicion is necessary in younger patients presenting the bilateral pain in shoulders, hips, and back, with elevated acute phase reactants."
-- Early onset polymyalgia rheumatica: two rare cases under age of 50:
https://pubmed.ncbi.nlm.nih.gov/28324118/
It's good that your doctor is checking for other conditions as there are conditions that mimic PMR. Not sure if you have seen this one but it's an easy read and might be helpful:
-- Diseases that mimic polymyalgia rheumatica (PMR):
https://www.medicalnewstoday.com/articles/diseases-that-mimic-polymyalgia-rheumatica
Were your erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels high?