Having Severe Joint Pain Suggestive Of Arthritis And How Can It Be Treated?

Last August I donated blood through Florida Blood Services, which I had done routinely and regularly for many years and received a letter back indicating that they had rejected my blood because of a false HIV positive, probably related to an auto immune issue like arthritis. They suggested I come back for a retest in December, which I did, and which confirmed the same issue, which prohibits my donating blood in the future. No one suggested that I should see a doctor about this, but since then I've been finding I have a great deal of pain in my joints, especially in the mornings. I tend to feel better when I'm moving. Now, I know that since I've looked up some details about the disease, I may be "suggestible" to the symptoms. But I'm wondering how complicated and expensive it would be to find out what's going on and what I should be doing about it. I'm age 65, retired, with plain medicare only and not a great deal of financial assets. I can deal with the aches and pains I have and don't really want to jump into consultation, testing and treatment that would be very expensive unless it were truly vital.