This can happen for a variety of reasons. From foot problems, obesity, which causes mine. It could be nerve pain due to diabetes.
http://www.epodiatry.com/foot-pain.htm http://www.drfoot.co.uk/ I'm sending you 2 excellent web sites, so that it might help you understand what you might be dealing with. It's also advisable that you see a foot doctor to help determine your particle reason why. Hope this answered your question. If so please press the accept button. And feed back is wanted. Gail