Is there any correlation with bad circulation?
I ask because I'm always the first to get cold hands or cold feet when the temperature goes down and I tend to get the leg cramps in the night after a day when I've noticed that I have had cold feet.

I am told that the pain is caused by a build up of lactic acid in the muscle not being flushed away in the blood stream, which also could be affected by the poor circulation theory. The lactic acid is generated by the muscle working and the problem is that the muscle has "switched on" and won't "switch off".
I always try tensing the muscle that is hurting and then relaxing it in an attempt to make it "switch off" naturally, and this works nine times out of ten. After that it's down to massage etc.