I Have Had Joint Pain In My Hands/wrists/ankles/feet/left Elbow/left Shoulder

I have had joint pain in my hands/wrists/ankles/feet/left elbow/left shoulder which have worsened over the last 3 years. It was a sudden onset with a fever and severe joint pain. I recently developed SOB with exertion and thoracic pain into my chest with exertion. EKG was WNL and blood work is WNL except mild elevation of CO2 blood levels. Scheduled for a treadmill stress test next week. Could this all be related to an auto-immune disorder? Initial RA testing was negative.