What is the cause of my foot pain?

If you are working in kitchen or running after your children restlessly. You need some rest. Massage you feet and toes with oil or moisturizer before you slee at nights. Take multivitamins for couple of week or so.
When you are cooking, sit on bar stool. Don't stand continuously for long time. Take more breaks. Don't wear high heel sandles. See what happens.

If you weigh more, try to loose some weight by adding fresh fruit and vegetable juice, nuts to your diet, reduce other stuff.