Pain on the outside of both feet.

Hi. I really hope someone can help me here.

I used to play Badminton as a kid at a fairly high level 8 years ago - Now I am starting up again (Age 24) and have played for some weeks now. It's great to play again but I have a problem. During last training i started to feel this pain on the outside of both of my feet, the next morning I could barely walk. This pain has been going on for about a week now and it has become better but still hurts and I am afraid it will come back when I play next time. I threw out the cheap Badminton shoes that I started to play with (which also was really narrow) and have bought myself some new ones today from Bonny sports which feels very very comfortable.
I really hope it was the cheap shoes that was the reason for the pain but could it be something else, maybe starting up too hard or something?
Anyway my question is:
Have any of you experienced this pain on the outside of the foot (right beneath the knot on the little toe) and what did you do to solve the problem?

I really hope some of you can help me out because I love this game!

- Rasmus