Depends. Depends where they are located. If they are around the sides of the heels, this is piazogenic papules = herniated fat and nothing to worry about. Another possibility are plantar fibromas if on the bottom of the feet. But, you should never full around with "bumps". See a podiatrist or dermatologist.
Many Things. There are several things these could be. Cysts, fibroma, lipomas. Most all of these are benign. If they begin to hurt more or grow larger I would have them checked by a physician. It would be helpful to see a physician now to get a base line on whwere the bumps are now so it will be easier to track them and see if there are any changes to them.
Small lipomas. It is common to have small dermal bumps inside of the heel and also on the tops of toes.