Rheumatoid Arthritis Support Group
Rheumatoid arthritis is a chronic, inflammatory, multisystem, autoimmune disorder. It is a disabling and painful condition which can lead to substantial loss of mobility due to pain and joint destruction. The disease is also systemic in that it often also affects many extra-articular tissues throughout the body including the skin, blood vessels, heart, lungs, and...

No, I didn't have that kind of reaction to Moderna when I had it. What RA meds are you on? I'm on MTX, Plaquenil, and Rinvoq and 5mg of Prednisone. Have you called your Rheumatologist? You may need to have your meds adjusted.
The vax is still considered experimental so it is possible it activated something. They will need to collect the data to see if it happened to other people. I haven't heard that, but I heard it may have triggered alopecia areata in someone.
Keep us posted. I hope your flare subsides and it isn't a progression.