Maybe this is a bit odd... BUT!
I've been getting extremely painfull foot cramps for years now, and I've always been getting them in bed of all things. I get them when I'm swimming also.
But it's puzzling me that it's usually when I'm just lying still. One minute I'm dozing off, then bang my foot cramps up, and it's unbeleivably painfull.
Does anyone else have a similar problem? Or know what might be wrong? I've never bothered going to the doc with this because it's something that always just happened, and I never thought much of it. But could there be something to it?