<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, I have noticed that my scrotum is very swollen and I can feel a large mass in it. What could be the reason for this?  <response>: Well, based on your symptoms, it sounds like you may have a male genitalia infection, also known as epididymitis. Its important to get it checked out and treated right away to prevent complications. 