What part of the foot hurts? Is it more towards the heel or the between the toes and the heel? Either way you might have plantar fasciitis. I still have it but I lost a few lbs and it went away.
Before that I went to an orthodic doc and the first thing he did was shoot a cortisone shot in my heel (yeah that sucked). That helped but still had pain. They ended up taking a mold of my feet and had custom inserts made for my shoes. They worked but like I said, I lost a few lbs and the pain went away.
You could always go to a meijer and find their Dr. Scholls machine thing. You stand on it, it measures your feet, some other crap and tells you which Orthodics to buy.
https://www.drscholls.com/custom-fit-orthotics-kiosk-locator/
It's worth a shot and only will set you back about $50 or so.