I've heard the pain can be compared to a woman giving birth! My uncle had a really big one and needed an operation, I can't believe he endured the pain >.<' ...
Recently I thought I was getting a Kidney stone, however it was infection on both Kidneys, it too hindered me with huge amount of pain, the right Kidney has stopped hurting though.
I was in the Emergency Room two nights ago, I was injected with a pain killer (first time), I must say, it was such a great relief!