Well I don't want to confuse you, but I actually have both RA and Lupus. I have had lupus a lot longer than RA. It can be very difficult to tell which disease is bothering me at times.
However, I can say that like Lynnwood and Joy, I have the burning sensation, but I also have the stiffness. You mentioned that you're very stiff in the morning and it lessens through out the day. I do the exact same thing with my wrists, ankles, toes, and fingers. Usually, by 10 am or so the stiffness is totally gone.
My joint pain is still there as is swelling at times. According to my Rheumy normally with most RA patients they have stiffness in the morning and it eases as the day goes by. It's quite possible that you do have RA and not Lupus. Or, shame on me for saying, but you may have both RA/Lupus.
My RA factor was positive, but the confirming factor was an MRI. My Rheumy ordered an MRI of my hand that was the worst. The MRI showed that my joints in my thumb and middle were already starting to deform. Maybe, you could ask your Doctor to order and MRI to rule out the RA once and for all.
Hope I helped some. Hope you feel better soon and get a diagnosis real soon and start treatment.
DX- RA, Lupus, Fibro, LGL Leukemia, Pulmonary Hypertension, Bells Palsy, Gastroparsis, Blood Clots, Glaucoma, Chronic Pericarditis & Pleurisy, Severe Anemia. Way to many medications to list.