The most common cause of groin pain is a muscle, tendon or ligament strain, especially in athletes who play stop and go sports. Groin pain might occur immediately after an injury, or pain may come on gradually over a period of weeks or even months and will be worsened by continued use of the injured area. Less commonly, a bone injury or fracture, a hernia or even kidney stones might cause groin pain. Although testicle pain and groin pain are different, a testicle condition can sometimes cause pain that spreads to the groin area.