Tennis elbow or lateral epicondylitis pain is experienced on the outside of the elbow and can refer into part of the upper arm or down into the forearm. It’s a painful condition cause by repetitive use of the wrist extensor and finger extensor muscles. Tennis elbow is inflammation of the extensor tendon that joins the wrist extensor muscles in the forearm to the bone on the outside of the elbow (lateral epicondyle). With repetitive use the tendon becomes strained, inflamed and damaged. It can be caused by playing tennis but other activities, like poor positioning while working at a computer, mousing & painting can also be the source of the problem, to name a few.