Pain in ball of foot when big toe extended

I have a pain in the bottom of my foot close to the front(near the ball of my foot). It is only painful if i put pressure on the spot in the middle of my foot, or when i walk and basically push off with the big toe. I went to see the doc yesterday, but he only confirmed no fractures through xrays. I would really like to know if anyone has any thoughts on what this might be as i tweaked it a few times while sleeping last night. When i got out of bed this morning, i noticed that my foot looked a little swollen. No bruising anywhere. And if i extend my big toe with my foot off the ground, that causes pain as well.