Exactly what is it and where does it hurt? Heel? Ball of the foot? Arch?
There’s 3 nerves that extend out under your foot that start out near the outer edge of the heel about 2/3 of the way back. It hurts at that exact spot.
These Powerstep Protech insoles have a thicker heel section but I think the main part is they are built up substantially in the arch section which lifts the foot up and helps keep the weight off your heel.