I used to work full time in a grocery store, and I understand what you mean about the pain. They provided supportive, sturdy rubber mats for us to stand on, but that didn’t help enough.
I had orthopedic inserts made from the shape of my feet, and cortizone shots to my heels, and that helped for a while, but the only thing that helped long-term was quitting that job. I wish I had quit sooner, before the damage was so permanent. Even though I quit five years ago, I still have occasional pain, especially when I’ve been off my feet for a long period (sleeping, or at my desk job) and stand up to go somewhere. It still hurts like that for a few minutes until everything gets stretched out.
I know it’s not really very practical advice, to stop damaging yourself when you probably need your job. It’s a trade-off, though: what you need now, to how much future pain you are willing to risk.