Epididymitis occurs when there is inflammation of the epididymis (a curved structure at the back of the testicle ).  This condition usually presents with gradual onset of varying degrees of pain, and the scrotum may be red, warm and swollen. It is often accompanied by symptoms of a urinary tract infection , fever, and in over half of cases it presents in combination with orchitis .  In those between the ages of 14 to 35 it is usually caused by either gonorrhea or chlamydia . In people either older or younger E. coli is the most common bacterial infection.  Treatment involves the use of antibiotics. 
Testicular pain is pain or discomfort that is felt in one or both testicles. The pain may originate from the testicle itself, or it may be the result of other conditions affecting the scrotum, groin or abdomen. Though there are numerous medical conditions that can cause testicular pain, it is important to understand that a few of them constitute medical emergencies that require immediate medical attention in order to prevent impairment or loss of testicular function. Testicular pain can be an acute (short-term) or chronic (long-term) condition. The testicular pain may be constant or intermittent.