Testicular pain may be caused by diseases of the testicles themselves, or by neighboring organs; penile inactivity, which is also known as penile erectile dysfunction, may be caused by psychological factors, age factors, chronic diseases of the body, medication factors, and bad habits. 1. Testicular pain: (1) Diseases of testicle itself: for example, orchitis, epididymitis, epididymal cyst, testicular tumor and other diseases will cause testicular pain. (2) Diseases of neighboring organs: for example, prostatitis, prostate cyst, prostate cancer, seminal vesicle adenitis, etc. may also cause testicular pain. 2. Erectile dysfunction: there are many causes of erectile dysfunction, such as psychological factors, age factors, chronic diseases of the body (diabetes, high blood pressure), adverse reactions to medications (venlafaxine, etc.), smoking, alcoholism, late-night exertion and other bad habits.