Tennis Elbow - Tennis elbow, also known as lateral epicondylitis, is brought on by overusing the muscles inside the forearm. This contributes to pain and tenderness on the outer part of the elbow. It's popular amongst tennis gamers but can have an affect on anyone who does repetitive arm movements. https://www.theorthopaedicandpainpractice.com/why-is-my-elbow-swollen/?_gl=1*xbbxlb*_up*MQ..&gclid=Cj0KCQjwkt6aBhDKARIsAAyeLJ2krYJSOuy5mZksrNqH-VDjQwW1ScD49yD8BUWysDG6u6bJPCSbXVUaAuCPEALw_wcB