Last thursday, 3 am in the morning I woke up with very bad pain in my lower back. Hour later I was fine. Went to the doctor on Friday, urnine sample showed blood in the urine. Had a CAT scan Tuesday. Yep, 2 Kidney stones on the right side, 1 on the left in the bladder. How long do they take to pass? Could I have them for awhile longer? 3mm in size. My dad had them 3 times!