The website of your pain in tennis elbow is the place some tendons in the forearm muscles attach on the bone within the elbow. The pain is considered caused by swelling or thickening in the tendon to begin with and sooner or later degeneration (carrying) of your tendon.   Bonus: https://www.theorthopaedicandpainpractice.com/how-to-alleviate-tennis-elbow-pain-tips-from-a-medical-expert/