Hi. Thanks for your query. This is a classical history of a sudden pain in the testicle and can occur only in the following situation: -Commonest cause for a sudden pain in the testis which is referred to the stomach / abdomen is Torsion of the testis. In this the testis rotated along its axis on the spermatic cord blocking the venous return first and causing the pain. In some cases there may be a spontaneous de=rotation and the pain may just vanish away. - The less common reason can be severe orchitis, meaning inflammation of the testis , there may be accompanying urinary tract infection. -The diagnosis has to be made very urgently as within 6 hours the testis can loose function if the torsion is complete and is not diagnosed or treated by surgery. Hence urgent color doppler and ultrasonography and to be ready for an emergency operation is a must. Even if the torsion is relieved , you should go for fixation of the testis fast to avoid further attack, which can occur anytime. If there is UTI causing orchitis. get investigated and treated again on an urgent basis and for at least 3 weeks.