Pinky toe swollen and sore?

So yesterday I noticed that my pinky toe was kind of sore and I looked at it and it was really quite noticeably swollen. It's not broken or anything cause I haven't banged it or anything like that. I'm guessing it's because I wear Pumas which everyone knows are kind of tight and narrow and I didn't get them THAT long ago, plus I'm a cashier at a grocery store so I stand a lot. But still, what exactly is causing it to swell and be so painful?