I have not seen a podiatrist yet, but I will if it persists. I'm pretty certain it's not my everyday shoes that are the issue. Until now I have only noticed the pain during tennis.
I have noticed that my service motion is part of the cause. I use basically the same service motion as Federer, so when I start the motion by rocking to the forward foot and extending the back foot, it puts side pressure on the toe of the back foot, and then when I push off the back foot it kind of rolls over the side of the toe again. I have tried to adjust this, but so far I haven't found good way to do it.