Hello, thanks for using health care magic. Painful and swollen testicle is a medical condition requiring urgent diagnosis and management in order to maintain vitality of the testicle. There are two most probable causes which include trauma or infection. Blunt trauma causes contusions which can lead to localized inflammation and or hematoma resulting in to pain and tumefaction. Trauma has also been associated with torsion of testicle which is an extremely urgent surgical condition in the case of a complete torsion. Infections as well will manifest with pains and swelling and might involve the testicle it self or the epididymis or both. What you should do is consult your doctor for appropriate evaluation and tests such as urinalysis and doppler ultrasound of the testes. Best regards and hope this helps you. Dr. Achuo A. M.