Dear patient, Classical symptoms of kidney stones are: severe flank and groin pain, blood in urine, nausea/vomiting and restlessness. Sometimes it can be without symptoms, because depends on the size of the stone. Presence of leukocytes in urine, your mild lower back pain, frequent urinating and nausea , together they indicate you have urinary tract infection. For this I would recommend to drink cranberry juice and 3-5 days course with Bactrim twice daily to help fight bladder infections. Hope my answer was helpful for you.