What causes your heels to hurt after a long period of walking?

See below: Poor support my cause inflammation of the arch and excess strain on the plantar fascia.

Fracture or PF.: Could be many things, but the two most likely are either a stress frature or plantar fasciitis. The best way to know is to get an x-ray of your foot. Another clue is when it hurts: stress fractures are all the time, while pf hurts most with the first few steps in the morning, or after sitting for a long time. See a podiatrist to rule out nerve entrapment or tendinitis.