Welcome @malin70, I have never heard of massage therapy helping with PMR but maybe others have. Massage would probably have been that last thing I wanted to try with both of my occurrences with PMR. Since you mentioned your doctor changed your diagnosis to fibromyalgia one year later there is another discussion that mentions Myofacial Release Therapy (MFR) has been used to help a lot of different condtions including fibromyalgia. Here's a link to the discussion - https://connect.mayoclinic.org/discussion/myofascial-release-therapy-mfr-for-treating-compression-and-pain/.

I'm wondering if your doctor may have been correct to change your diagnosis since PMR is sometimes difficult to diagnose and their are other conditions that mimic PMR.
-- Diseases that mimic polymyalgia rheumatica (PMR): https://www.medicalnewstoday.com/articles/diseases-that-mimic-polymyalgia-rheumatica

Have you asked your doctor about getting the Shingrix vaccine while you are still having PMR like symptoms and an elevated SED rate?