Scrotal distension may be caused by improper clothing, or it may be caused by diseases such as orchitis and epididymitis. 1. Inappropriate clothing: If men often wear pants of inappropriate size, such as tight pants, it is easy to cause pressure on the testicles, which in turn affects the local blood supply, so there will be scrotal distension and pain. 2. Testiculitis: This disease is mainly caused by pathogenic microorganisms such as bacteria, virus, Chlamydia trachomatis, mycoplasma, etc. It can be transmitted through sexual behavior, and secondly, it may also be caused by mumps and testicular surgery. Patients will have symptoms such as testicular enlargement and pain, and if abscesses are formed, there will be fluctuating sensation locally. 3. Epididymitis: the main cause of this disease is bacterial infection, followed by gonococcal and Chlamydia trachomatis infection, and congenital vas deferens obstruction, urinary reflux and so on. Swelling and pain at the patient’s epididymis is a common clinical symptom of epididymitis, which can manifest as scrotal distension. There are many causes of scrotal distension and pain, and it is necessary to go to the hospital and do relevant examinations to clarify the cause of the disease.