The left side of the lower abdomen pain left testicle pain may be the left side of the ureteral stone, left epididymitis, chronic prostatitis and so on. 1. left ureteral stone: ureteral stone will appear abdominal pain symptoms, at the same time can be accompanied by radiating pain, so the left side of the ureteral stone can be manifested as the left lower abdominal pain with the left side of the testicular pain, but also can be accompanied by hematuria, nausea, etc., the urinary ultrasound/X-ray and other tests can assist in the definitive diagnosis. 2. Left-sided epididymitis: epididymitis can present with radiating pain in the lower abdomen or groin of the same side, therefore, left-sided epididymitis can manifest as vague pain in the left lower abdomen accompanied by testicular pain on the left side, and may be accompanied by fever, inguinal tenderness, etc. Ultrasonography of the epididymis can assist in making a clear diagnosis. 3. Chronic prostatitis: Chronic prostatitis can be characterized by radiating pain in the testicles and lower abdomen, so chronic prostatitis can be characterized by vague pain in the lower left abdomen accompanied by pain in the left testicle, accompanied by increased nocturia, urinary urgency, urinary pain, etc. Ultrasound of the prostate gland can assist in the definitive diagnosis. There are many causes of left lower abdominal pain and left testicular pain, it is recommended to consult a doctor in a timely manner to avoid delays.