I am 100% pro science and believe in vaccines. Having said that, I did get my 3rd or 4th covid shot (booster) in Nov '23 and the PMR started in my thighs in Jan '24. I don't think they're related but who knows.
The other thing that occurred about 6 mos prior was that I stepped up my exercise program to include a lot more pressure on my thighs. When the PMR pain hit, I was completely sure that I had over-exercised. Which may have been the case. When it spread to my shoulders, I knew something more was going on.
I do think there are things that cause PMR but no $ to do the research.
I will say I'm iffy about getting the current covid booster. Haven't had any shots of any kind since pmr.
Best to you. Hope your recovery is swift.