Years ago I had this same sort of thing happen but they were not completely sure it was kidney stones. What basically happened in both cases is that all of a sudden I get these cramps in my groin. Then the intensity very quickly changes and the cramps turn into very sharp and painful pains. The pain is so bad I have to walk bent over. Then I suddenly have the urge to urinate and after I do the pain is gone.
Has anyone ever had anything like this with kidney stones?