One er visit said 5mm other er visit said 8mm kidney stone in lower kidney. can a stone still hurt while in kidney? was told it should not be hurting

Renal stone: Usually the pain is caused when a stone goes out of the kidney into the ureter. A small stone that stays in the kidney will not be a source of pain.

Small stones: Most small stones don't cause symptoms while embedded in the kidney. What was the imaging method used to detect the stones ? CT scans are sensitive to pick up all stones US may miss some and X-rays can miss many. Often a passed stone can cause pain but not be visible. The 3 mm size diff is small.