Anytime a person does the same activity over and over, there is a risk of developing pain and problems. You may have developed a condition called tennis elbow, known to doctors as lateral epicondylitis. With this condition, overuse causes damage to one tendon/muscle unit in particular.
A doctor can determine the exact cause of your painful symptoms. In the case of lateral epicondylitis, most patients become symptom-free with the use of medications. Sometimes other kinds of treatment are necessary, such as physical therapy, injections, or surgery.