What is the pain in my foot?

I had my first day at work as a sales assistant in very busy sports clothing shop yesterday. I was on my feet all day in trainers. Im not a sporty person and dont usually wear trainer. when i got home and took my trainers off about half an hour later i got a severe pain in the side of my left foot. Its worse when i stand or walk. Will this pain be away by saturday asi working again then?