Some good answers already. Take an extra pair of comfortable shoes in a different style to work every day, and change at lunch time. Sit whenever you can. Alternate standing on the left and right foot, to take the weight off one. Lose weight if overweight.
If your workplace only has a hard floor, ask if a more comfortable surface could be supplied, and if the answer is unfavourable, ask if you could provide an acceptable one in the form of a thick rug or rubber matting. Consider seeking a job where you don't have to spend so much time on your feet, as the problem may well be long term.
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When you get home, bathe your feet in Epsom salts / magnesium sulfate; see https://www.google.com.au/search?client=opera&q=magnesium+deficiency%3B+pain&sourceid=opera&ie=UTF-8&oe=UTF-8
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