Can kidney stones cause pain while still inside the kidney?

For months I've had stabbing pains in my lower back and after multiple negative ultrasounds a CT scan found a 9mm stone inside my right kidney. My urologist tells me that the stone is still inside the kidney itself and should not be causing me any pain and booked me for a followup after a few months. In the meantime he's telling me to up my water intake to try and flush it out as he's seen stones as big as 1cm pass naturally. I think he's nuts since I'm feeling it in there while it's still in the kidney. I can't image what it would be like if it ever gets inside my ureter. Has anyone ever felt pain from a stone while it's still inside the kidney itself? Since they can't see it in an ultrasound, blasting it is out of the question, but he did say that he could go in through my ureter and break it up and remove it that way if needed, but he believes that I can pass it myself.