Epididymitis is an inflammation of the epididymis, the coiled tube behind the testicle that stores and carries sperm. It is most common in men ages 20-39 and is usually caused by a bacterial infection spreading from the urinary tract or an STD. Symptoms include testicle pain and tenderness, painful urination, and fever. Doctors evaluate with exams, tests, and imaging to diagnose and rule out other conditions, then treat with antibiotics and anti-inflammatories. Leaving epididymitis untreated can cause permanent damage.