Swelling sensation in the perineum under the testicles, like cramps, is likely to be caused by orchitis, testicular torsion, ureteral stones and epididymitis. 1. Testicular inflammation: usually caused by bacterial, viral infection and other inflammation, manifested as testicular swelling, pain, some patients may be accompanied by fever and other systemic manifestations. 2. Testicular torsion: there is no clear cause of the disease, and it is considered to be related to testicular injury, age and heredity, etc. In the early stage of the disease, it is mainly localized hidden pain, and with the development of the disease, it will have localized reddening of the skin, swelling and severe pain, and in serious cases, there is a cramp-like pain under the scrotum. 3. Ureteral stones: patients with ureteral stones usually have the symptom of lumbar pain, and if it is the lower part of the ureter, there may be pain in the lower abdomen, which will radiate to the external genitals and scrotum and other parts of the body, making it painful. 4. Epididymitis: mostly caused by bacterial infection, may also be caused by urinary reflux, the patient will have epididymis hardening, enlargement of the manifestations, may also appear below the scrotum pain phenomenon. There are many other causes of such symptoms, and it is recommended that patients should go to the hospital in time after the occurrence of this situation, and then take active treatment after a clear diagnosis.