Golfer’s elbow, Tennis elbow?… but I don’t play either sport!
Well, you don’t have to. More properly called medial epicondylitis and lateral epicondylitis, these two conditions are often not the result of golf or tennis, but they are common injuries in those sports.
Almost all of the muscles that control your fingers and your wrist are located in your forearm, not in your hand. The muscles which flex (curl) your fingers and wrist all converge to a single attachment point on the side of your elbow closest to your torso (the medial epicondyle), and all of the muscles that extend (straighten) your fingers and wrist attach on the outside of your elbow (the lateral epicondyle).
The best way to see this on your own arm is to bend your elbow at 90 degrees and point your thumb up. Now bend your wrist left and right, and, by touching near the bony parts on either side of your elbow, you can feel the two muscle groups working.
As for the naming of these two conditions, It just so happens that swinging a golf club tends to put excessive strain on the flexing muscles and swinging a tennis racquet tends to strain the extension muscles. Whatever the cause for you, when these attaching tendons get injured and inflamed, the result is painful tenderness in the local area, and increased pain when performing the flexing or extending movements (depending on which injury you have).
You can do stretching exercises to help relieve this pain, get some arm braces to help compress the area, take painkillers, or just rest and hope everything goes back to normal. But if it were me, I would come in for a few treatments of laser therapy right away. You’ll probably be surprised at how quickly it will take away the pain and inflammation.