Is there greater clinical improvement in long term pain and function when patients receive two PRP injections instead of one? This is a double-blinded randomized controlled study to determine the ideal treatment regimen for treatment of chronic lateral epicondylitis (tennis elbow). The investigators will compare pain visual analog scale (VAS) scores and functional Disabilities of Arm, Shoulder, and Hand (DASH) Questionnaire scores of patients receiving a single PRP injection and two PRP injections.