Ow, my foot hurts

So this is kind of random, but here goes…
All winter I was extremely lifeless and did absolutely no physical activity. That’s sort of wierd for me since I’m an extremely athletic person, not that I play any organised sports or anything, but I’m good at any sport I want to be basically, well not necessarily good, but good enogh. So then the last week or so I’ve been “exercising” for extended periods of time. For instance playing dance dance revolution on the ps2 which is extremely tiring if you play non stop for like an hour or 2 every day… and then playing tennis, but since we can’t find nets, playing on a 16 foot tall fence, haha. Anyway, it’s all good and stuff and I feel great but my left foot just kills. The arch hurts any time I put any pressure on it, IE walking. I don’t know how to describe the pain, it’s really sharp and annoying, and I only have it in the one foot.
Does anyone know any excersises or anything I can do to tone down the burnage?
Thank ya kindly.