You are describing a pump near your scrotum that is associated with mild pain. I recommend that you be examined by your primary care doctor
. There is a possibility that it could be a inguinal hernia
. Hernias develop when there is weakening of the abdominal musculature. There is an area called the inguinal canal where hernias can develop. Parts of the bowels can end up traveling in the inguinal canal and into the scrotum, which would cause an enlarged scrotum on one side. It is associated with pain. It is worsened with increased abdominal pressures such as coughing. Hernias can sometimes be pushed back in where they originated. There is risk of the hernia rotating on itself which would cut off the blood supply to that portion. This would cause a lot of pain. Other possibilities are epididymitis, hydrocele, or malignancy. Epididymitis is an infection of the epididymitis. It could be caused from sexually transmitted disease such as gonorrhea. A hydrocele is a fluid pocket that drained in an area of the scrotum. Malignancy should also be ruled out in this situation. You should make an appointment with your primary care doctor to have your scrotum examined to determine if you need any further tests such as an ultrasound
of the scrotum.