Not a Kidney Stone, but a back/knee problem
 

My boss just related a story to me that is worth passing along. Two days before he went for his flight physical, he thought he was passing a kidney stone. Went to the ER, who found nothing.
Worried that this was a real show stopper (and it is for FAA and most medicals), he asked the medical examiner about it.
The doctor asked him about the sypmtoms, and then, without further ado, reached down, and gave a very large pull on one of my boss's legs. Solved the problem.
Turns out the doctor knew about some connection between back/knee issues and supposed kidney stones!! Wrote 'misdiagnosed' on the medical report, and all was well.
Passing this on in the hopes that someone else might benefit from it.