Your body needs some sodium to function properly because it: 1  Helps maintain the right balance of fluids in your body. 2  Helps transmit nerve impulses. 3  Influences the contraction and relaxation of muscles.
Some of the conditions that can cause a testicle lump, swelling, and/or pain include: 1  Torsion of the testicle. 2  Injury. 3  Infection. Hydrocele. 4  Varicocele. Epididymal cyst/spermatocele.  Inguinal 1  hernia. Kidney  stones.
Some of the swollen left testicles with pain can be due to serious health conditions such as testicular cancer, but mostly, cancer in the testicles is accompanied with other signs and symptoms such as hard lumps in the scrotum and lower back pain.