What muscle is affected with golfers elbow?

Having suffered both left and right elbow problems from tennis and then golf - the tendons at the joint get inflammed and slight fibrous tears actually rub against the bone causing the pain. Severe cases require surgery to sc away the tears. Initial treatment is rest and anti inflammatory drugs, followed by injections of cortisone or soluble steroids to dull the inflammation. This is followed by exercizes to strengthen the forearm muscles to relieve the stress on the tendon. Hope you are not suffering - see a specialist. Rest and recover and don't come back too early.