Feet get really cold and painful when I go to bed. Why? How can I help prevent this from happening? I exercise 5 days a week by the way.

Vascular or Nerve ca. Pain as you describe is either of an arterial vascular issue or nerve abnormality. Cold temperatures at night can aggravate both causes. Vascular issues could be from decreased coronary output, peripheral artery blockage or vasospasm. Nerve pathology such as polyneuropathy from metabolic abnormalities such as diabetes mellitus can also give such symptoms. An in depth evaluation is necessary.