Possible causes of lumbago with testicular pain: 1. Acute orchitis or epididymitis. In this case, acute enlargement of testicles and epididymis with obvious pain can occur. The inflammation can involve the spermatic cord, so there is radiating pain in the small abdomen and radiating pain in the lower back. On physical examination, the testicles on the affected side can be seen to be obviously swollen, and the epididymis can be enlarged in size with obvious pain to touch. Ultrasound examination of the testicles and blood tests are needed to further confirm the diagnosis. 2. Testicular torsion. The testicle is twisted clockwise or counterclockwise along the spermatic cord, thus causing testicular ischemia and acute pain. Physical examination shows that the testicle on the affected side is elevated and the testicle is fixed in position and cannot be easily pushed by hand. Ultrasound examination of the spermatic cord and testes is needed to rule out torsion. With the prolongation of ischemia, radiating pain in the spermatic cord and lumbar region may appear, and immediate surgical repositioning treatment is needed after diagnosis.