Both lateral epicondylitis “tennis elbow” and medial epicodylitis “golfer’s elbow” are results of overuse of the elbow with lateral epicondylitis being the most common. 

They are a result of minor tears in the tendons of the muscles that flex and extend the forearm.

Pain is felt where the tendons attach to the elbow.  Any task that requires grasping and squeezing (shaking hands, opening jars, turning doorknobs) causes pain.