What is the cause of dull, random, occasional, testicular pain?

Depends. Testicular pain can have many causes depending on age, exam, and symptoms, but in my practice, when a man of about 50yo is seen w/ the above symptoms, i usually end up finding by examination either a prostate infection and/or infection of the epididymis, which can be treated with antibiotics.Std's may be found in young men w/ the above symptoms, but there are other causes also.Please see ur doc.