Ice, rest, NSAID
Does your pain come when you do certain activity? Is it acute pain or chronic? Have you injured your elbow, recently or in the past? Any "itis" implies inflamation, usual treatment: ice,[alternate with heat], immobilization
/rest, & antiinflamatory meds.
If it is not getting better, see either an orthopedic surgeon to exam the elbow, or rheumatologist to investigate the cause of joint inflamation.