I am experiencing the same leg burning, I am 76 and in my 40's diagnosed with MG and took Mestinon for a few years, then I stopped making red blood cells Pure Red cell anemia, then autoimmune hepatitis and now RA and Sjogren's too. My mother passed away from undiagnosed Rheumatoid vasculitis and I believe I have this too but the Rheumatologist does not comment or offer any advice so enter the anxiety and depression, I have tried a few medicines but get too sick from them, I give up but hope you have better luck than I did.