What causes left testicular pain upon waking up?

Left testicular pain upon waking up can be caused by various factors: 1. Improper sleeping posture: Leg positioning during sleep may compress the left testicle, leading to local blood congestion and mild swelling. 2. Infection: Such as orchitis or epididymitis, which may be related to bacterial infection, presenting as testicular swelling, pain, and possibly accompanied by fever. 3. Varicocele: Left-sided varicoceles are more common than right-sided ones, with symptoms potentially worsening after physical activity and improving with rest. 4. Testicular torsion: Due to increased anatomical mobility of the testicle and spermatic cord, the testicle may twist around the axis of the spermatic cord, compressing and obstructing blood vessels, resulting in acute ischemia and potential necrosis. 5. Other causes: Conditions such as hydrocele or ureteral stones may also cause left testicular pain. If the pain persists or worsens, prompt medical evaluation and treatment are recommended.