Blood tests within normal limits do NOT rule out inflammatory disease! I have psoriatic arthritis (an inflammatory disease linked to psoriasis on the skin, with symptoms and treatment similar to rheumatoid arthritis) and when I first went to my (I have to admit, wonderful) GP, I had a finger so swollen I couldn't bend it. The inflammatory markers in my blood were (and always have been) within normal limits - common in psoriatic arthritis, even in cases so severe as to cause immobility. If you have ever had psoriasis, PA is worth looking into.