Tennis (or golfers) elbow is caused by inflammation of the tendons that attach the muscles in the forearm to the bone on the elbow. It is actually mainly caused by poor ergonomics and often mouse use is to blame.
Tennis elbow is a chronic condition and people can have it for years and never really get rid of it. In my case the symptoms started in December and by mid March it was not getting any better despite a program of stretches, exercises and foam rolling.
In the last 2 weeks I have purchased a flexbar and this $40 lump of rubber has made a huge impact on my symptoms. It has been proven in trials to be effective in a number of trials