When the bottom of your feet hurt it can be caused by a few different things such as simply standing on your feet too long or could be something such as Plantar fasciitis.
The Plantar fasciitis is a medical term that means inflammation of the fibrous tissue (plantar fascia) along the bottom of your foot that connects your heel bone to your toes.
Treatment for the condition Plantar fasciitis include things such as physical therapy, shoe inserts, steroid injections, and surgery.
If your foot pain on the bottom of your feet goes away within 1 or 2 days and doesn't come back then it may be that you just are putting too much weight on the foot and standing too long.
When I used to stand a lot as a cashier my feet would hurt at the bottom and would continue to hurt for the rest of the day.
But if it's not that then you could have the Plantar fasciitis condition and should see a doctor about it and get treatment.