Someone mentioned plantar faciitis on the previous page, which was my first thought reading the OP.
Are you at home and wearing slippers all day? I work at home and as I make jewellery, I prefer to stand at my bench when I work and tend to do this in my slippers. I've had plantar faciitis before so when the pain started, I wondered if it was the same again. I do have neuropathy in that foot, but that's an electrical pain which is different in nature. I just happened to be about to see my podiatrist so mentioned it to her and she concurred and recommended that I wear shoes with orthotic shaped soles to support my feet when I stand.
When you stand in flat soled footwear, the curve of your arch sags and consequently shortens that plantar tendon that runs along it. Then when you walk, it has to stretch to allow you to propel forwards and because it is shortened, it yanks on its anchor point front and back, often more so at the heel. That is incredibly painful and it gets progressively more inflamed, then becoming painful even as you're still. It's at its worst when you first walk after sitting a while and when you get out of bed in a morning.
I got a pair of clogs for working with shaped soles and with a couple of days of wearing them, it was significantly improved - along with doing the stretches she showed me too. Do you have a pair of trainers or walking boots that have arch supports - it might be worth wearing these for a while inside and see if this can bring about some relief. Do a search on-line for exercises and stretches for it, they're simple to do and brought me pretty rapid relief. Good luck, I hope you can find a solution quickly, foot pain is pretty miserable.
ETA: I missed the bit about seeing the podiatrist next week - hopefully they can sort something out for you.