Painful Calloused Feet

ok, my girlfriends feet have like...Hard callus's or whatever. If I could put a pic of it on here I'd let ya see em. But yea..the bottom of her foot is like one Hard callus all over it. Both of them. When I try to tickle them or lightly touch the bottom of her feet, it actually Hurts for. She feels pain from me even rubbing my hand across the bottom of her foot. Tops ok, just the bottom ones. She walks fine and everything. She walks a lot at her job, but she's quite often told me her feet hurt her while she's working. Not everyday, mostly on hard days so that might just be usual foot pains from walking. But its crazy how they hurt her when I try to tickle them.

Oh yea, her feet where like this even before she started the job where she walks around, so it didnt start from there, its been going on for a long while... any idea what that could be?