<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, Ive been experiencing some hand or finger pain, along with stiffness and tightness. Ive also noticed a lump or mass on my elbow. What could be causing this?  <response>: Based on your symptoms, it sounds like you may have lateral epicondylitis, also known as tennis elbow. This is a condition where the tendons in your elbow become inflamed, causing pain and stiffness in your hand or fingers. The lump or mass youve noticed could be a result of the inflammation. 