Sorry to hear about your back. The cold kidney thing doesn't make a lot of sense to me though particularly since it was .. well, not cold outside. Otherwise rational seeming people will happily sit in -25 to watch football and sometimes they're not even drunk whilst doing so.
The seats however ... I find are particularly uncomfortable and I will get back spasms after sitting in them too long. I'm wondering if you could have pinched a nerve especially if you've not had any prior problems. Another possibility is it could be a kidney stone or gall bladder stone. I had that over a period of a few weeks last year and it would literally drop me to the floor where-ever I was. Curiously it went away on its own before I was able to get it checked out.
I was going to say ya should have called ME too ya big doofus! Geez. I thought we were facebook friends and everything. Although if you needed help with peeing ... then I'm out. Kien can have that part allllll to himself.
Hope you feel better soon.