Why is the left testicle swollen and painful?

Swelling and pain in the left testicle may be caused by various factors, including but not limited to infection, inflammation, and trauma. For example, epididymitis can cause testicular swelling and pain due to bacterial infection spreading through the vas deferens into the epididymis. Additionally, testicular torsion may lead to acute pain and swelling, which is often associated with strenuous physical activity or injury. Furthermore, testicular swelling and pain could also be signs of serious conditions such as testicular cancer. Therefore, once such symptoms occur, prompt medical evaluation by a healthcare professional is essential to determine the underlying cause. Self-diagnosis or delaying treatment should be avoided to prevent irreversible damage to reproductive health.