What Causes Joint Ache And Numbness In Elbow?

My right elbow is puffy. A bag tight with fluid on the end. 6 weeks or so ago it was burning and puffy, black and blue about 3 inches above and below the joint but only for about 24 hours. The color disappeared and te puffy dissapated slightly and now has collectd on the end. Sometimes it burns, or the joint will ache and also causes slight numbness above and below the joint. What caused this and what is it? I cannot get I to an MD until Monday... Thank you