History noted, its good that you have passed one stone. Kidney
stone can cause urinary infection and in turn fever
if that stone has caused obstruction to your urinary pathway.Since the sonography
report does not show any obstruction, your urinary infection and kidney stones are co-incidental. Kindly consume a minimum of 3 litres a day regularly to wash out your stones as well as infection. Also take antibiotics as adviced by your physician.