Oh I had this same experience a few years ago and I was genuinely worried my heel bone was fractured and I was just walking on it every day. Check with a dr but mine turned out to be plantar fasciitis and it fucking sucks - put a water bottle in the freezer and use it to roll the base of your foot

That's pretty much the thing that helped me other than finally, when I could eventually afford them, buying expensive shoes that were actually comfortable and supportive, but that might be something a dr could convince winz to suss