The feeling of swelling in the testicles may be caused by physiological factors, testicular sheath effusion, acute and chronic epididymitis, acute prostatitis, varicocele, etc. 1. Physiological factors: Normal people can experience testicular congestion or bruising under certain circumstances, which may result in swelling sensation, such as sedentary, walking for a long time, wearing tight pants, after exercise, etc. Generally speaking, testicular swelling sensation can be relieved by itself after removing the triggering factors. 2. Acute and chronic epididymitis: acute epididymitis is a bacterial or viral inflammation of the epididymis, which is mainly manifested by scrotal swelling, fever, pain, swelling, sometimes accompanied by fever and chills and other systemic symptoms. Chronic epididymitis is the result of incomplete treatment of acute inflammation, which is characterized by long-term scrotal discomfort, swelling and pain. 3. Testicular syringomyelia: Testicular syringomyelia is a lump formed by the increase of fluid in the testicular syringomyelia sac, which can be caused by inflammation, trauma, infection and other factors. When the amount of fluid is large, the affected side of the scrotum can be swollen, falling, pulling sensation and other symptoms. 4. Varicocele: refers to the abnormal tortuous expansion of the veins in the spermatic cord. Primary varicocele is related to the underdevelopment of the spermatic vein valves and the weak wall of the veins, etc. The patient’s main manifestation is the affected side of the scrotum is swollen, pain, and a feeling of swelling, aggravated by standing or walking for a long time, and relieved after lying down. Varicocele is one of the most important causes of male infertility. In addition to the above diseases, acute prostatitis, orchitis, testicular tumors can also cause testicular swelling, it is recommended that patients go to the hospital as soon as possible to find out the cause of the problem and then be treated accordingly.