What could be wrong with my foot/ankle that hurts every night?

Need more details. To receive an answer that will be more helpful, you need to give more information...Your health status, any problems such as gout, diabetes or blood pressure concerns. You should state how long it has been a problem and what you do to make it feel better. Also tells us what it looks like. Is it discolored, swollen or point tender. The more you tell the better the answer.
Abnormal. This is an abnormal situation and needs to be checked since it could be related to a circulation problem of problem with the nerves.