Hi there!
Aside RA, arthritis involving multiple joints or polyarthritis can be caused due to a few reasons like gonococcal arthritis, non-gonococcal reactive arthritis, rheumatic arthritis, osteo/ degenerative arthritis, serum sickness, secondary to inflammatory bowel disease, connective tissue disorders, autoimmune disorders like SLE, associated with vasculitis, psoriatic arthritis, polychondritis, gout or pseudogout, haemachromatosis, secondary to a few metabolic and endocrine disorders etc., just to name a few. I would suggest getting this evaluated by a rheumatologist for an accurate diagnosis and appropriate management.
Hope this information helps.
Take care!
I am sorry you are in so much pain. You might want to look into hemochromatosis-- to much iron.
http://digestive.niddk.nih.gov/ddiseases/pubs/hemochromatosis/
I hope this helps,
achilles2