Then take your breaks as scheduled. Bring a Doctors note in if needed. Worse case scenario is they’re always hiring retail. Your health is more important.

Do you have the means to get a doctor to check this out? Because this sounds like it’s severely impacting your life and job, so if there is a solution to this you need to try. Other than that, I completely agree with Jaymail. Bring in a doctor’s note and take your breaks when you need to, if at all possible.

Sounds like you have develop neuropathy or possibly severe carpal tunnel definitely time to get checked out by a doctor.

OP, I have a special sympathy for your condition. I developed neuropathy from chemo (I am a cancer survivor). My feet can feel like they are on fire from just walking and standing - Though ironically a certain amount of daily walking helps. First, you need to see a doctor who can help or at least understand the problem. There are medications that can help (though most have serious potential side effects) and there are OTC supplements and topical things that help (I find a mix of CBD and frankincense essential oil is helpful applied topically - I make my own mix). A neurologist can also suggest supplements and if need be prescribe a medication… Secondly, unless you are very lucky this is the start of a long term condition and you may need to re-think your career choice to minimize time spent on your feet.