Tennis elbow occurs when tendons in your forearm are overworked and become inflamed. Commonly this is due to either repetitive movements of the wrist (RSI) or when the wrist is held in a static position for extended periods (common with prolonged keyboard usage).
The pain from Tennis Elbow (its proper name, Lateral Epicondylitis) presents on the outside of the elbow, normally when the muscle is being used (or if you gently press into the area). It’s not uncommon for the pain to be felt further into the forearm over time, sometimes as far as the wrist, causing pain or weakness when holding or twisting objects.
As with a lot of issues that I treat, problems start when the body is unable to meet the demand placed upon it. With Tennis Elbow, this could be due to a weekend of gardening (pruning flowers or trimming hedges back), or after tackling that DIY that has been put off for too long (hammering and screwing movements).
Treatment not only focuses on the painful area, but looks further afield to address the underlying cause, whether that is issues is with the neck, shoulder or spine.