Obstructing kidney stone, no more pain

Had excruciating pain beginning of December. Ultrasound showed nothing. CT scan showed us 6 mm stone, obstructing, kidney slightly swollen. I’ve had zero pain ever since. Had an appointment with my neurologist today. Who’s going to send me for another ultrasound to see if they’re still swelling in the kidney. He thinks I may have passed it without pain. wouldn’t an obstructing stone Cause continual pain? Maybe it did pass. First time I’ve had one so I have no idea.