Tennis elbow is a common type of injury that occurs when a tennis player, golfer, or other athlete uses their forearm muscles and tendons too much. It typically causes pain in the elbow and wrist area. The injury may also cause swelling in the muscles and tendons around the elbow joint.
Other causes include repetitive activities that involve gripping or twisting motions with the hands, such as painting, playing video games, writing, typing on a computer keyboard, or using an electric screwdriver.
Common symptoms

forearm and/or wrist
Pain in the outer forearm and/or wrist

Pain in the elbow
Pain in the elbow

Pain that worsens
Pain that worsens with activity

Stiffness
Stiffness in the wrist, hand, and fingers

Tenderness
Tenderness on the outside of the elbow

strength
Weak grip strength