No one has mentioned plantar fasciatis. This inflamation of the nerves in the feet can cause extreme pain. It can run on the edge of the foot and the bottom. It can be painful in the heel. I was in therapy twice. One needs to flex the feet by grabbing the foot and bending it back, stretching the fascia on the bottom of the foot. Also one can take a towel or rope, make a loop for your foot and ly on your back slowly lifting the leg just enough so you feel it a little. Do both feet and leg exercises and stretch the hamstrings and calf three or four times a day. Ice the feet once a day.
Drink plenty of liquids and spend some time off the feet. Your body will tell you when you need to be off your feet. There are so many causes for painful feet. Proper supporting shoes are very important. A podiatrist has a list of the brand and model of shoe that will help your feet.
I sometimes think that footpain might have something to do with allergies. If one has been tested then eliminating the culprit may help.
Some people have to follow the regiment above just to stay reasonably out of pain. Pain is your friend in that it tells you something is awry. I do also wonder at hormonal reasons for foot pain. It sure is miserable to not know the cause but sometimes one just has to find a regiment or exercise that helps and work on it.

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