Janbo - sound like kidney stones to me. The best way to describe where the pain is, is to imagine putting your hand around you waist, but a tiny bit higher, so the pain is both sides of the body. As the front a little, but mostly at the back.
it's not so much a sharpe pain, but starts off as a nagging ache that just gets worse and worse untill you just can't bear it.
If it's is kidney stones I find that a hot water bottle, nice DH's warm hands or similar helps. The consultant also swears by drinking lots and lots of water as aapreventative and to relieve the pain. You are supposed to drink so much that your urine has no colour whatsever.
the treatment usually is lithotripsy if your in London or nearby the best unit is at Guy's. It's basically sound waves that shatter the stone so you pee it out - it doesn't hurt a lot of people and wosses like me are given a painkiller and kept in for a couple of hours. I have had a operation too - but it's all long and boring.
I would go back to the dr and say you think it may be kidney stones, if you have to over play the pain - do it to be taken seriously as it can get v v painful. My consultant recently got a stone and he was shocked even as an expert how painfull it was.
Oh yes, and there is some thought that stones can start after pg, my DD was 10 weeks old when i first went into A&E wih the pain.