Started Out Last Tuesday When I Woke Up Feeling Like

Started out last tuesday when I woke up feeling like a bone spur at the very top of my elbow. Just to barely tap it hurts badly. Next day my elbow had a baseball size know and was very sore and felt like my tendons were all tight,knotted up feeling to where it hurt to hardly bend it. Thursday it had just gotten little bigger and it would just throb unless I was standing or sitting to where I could just hold it just right. The pain almost unbareable. By Friday It looked like it had started moving into my forearm area and I just couldnt stand it anymore so Friday evening I went to the hospital. I was admitted and treated for cellulitis of the elbow for 3 days. They did a exray, ultra sounds, took blood samples, cultures of my blood ( which everything blood related came back normal ) the whole nine yards and really couldn't say really what it was. Released yesterday with an MRI scheduled for Tuesday ( in 6 days ) Any thoughts, or inputs????