I'm an old kidney stone pro, only 30 + stones. The largest I've passed unassisted is 4mm x 7mm. Let's just say it kinda hurt. I've had pains that range from hot spike going down my mid to lower back to some that feels someone is pulling on a testicle. The best thing is to get to a Dr. and get checked out. They will probably do a CAT scan to get a good image of what's going on.

One of the best treatments for getting large kidney taken care of is lipsitripsy (sp). They bomb the stone with concentrated ultrasonic waves that shatter the stones into passable pieces.