Cramps in my toes

From: lind28

I am a 39 year old, healthy woman, with no medical problems whats so ever.  I walk alot, because of transportation problems, so I use my legs and feet constantly.  For a long time, I have had problems with my toes.  When I'm in an air conditioned enviroment, like a store, my toes start to cramp severely.  I try to get enough calcium in my food, because calcium supplements hurt my stomach.  I also started taking potassium and Magnesium vitamin supplements.  I've tried as much as I could to stop these painful cramps.  Recently I started getting cramps in my toes at night, and everytime I stretch my foot, my ankle would make a cracking noise, but no pain. What do you think is going on with me.  I'm thinking its because I walk alot, but that can't be the case.  Walking has kept my heart healthy and is maintaining my weight.  I'm 5 foot 2 and weight 120 lbs.  I also wear comfortable shoes.