Orchitis signs and symptoms usually develop suddenly and can include: 
Swelling in one or both testicles
Pain ranging from mild to severe
Fever
Nausea and vomiting
General feeling of unwellness (malaise)
 The terms "testicle pain" and "groin pain" are sometimes used interchangeably. But groin pain occurs in the fold of skin between the thigh and abdomen — not in the testicle. The causes of groin pain are different from the causes of testicle pain.