My Son Is 15 On Enilopril 10mg Twice A Day

My son is 15 on enilopril 10mg twice a day and amnilopine not sure how to spell it he has lost some weight but gotten taller he has been check it is hereditary for high blood pressure he played ball base ball yesterday and dove for a ball he didn't hurt yesterday but today he is hurting on the right side about 2 to 3 inches above his naval to the right he has hemeroids bad no appetite what can this be