So I have been doing lot's of running which I usually do in the winter but in the past week, all of a sudden the top of my left foot is killing me. Nothing has changed in terms of shoes/socks/distance and I am wondering how the heck I could hurt the top of my foot. If I dropped something on it, I would have some pretty good bruising and there is none. I've cut the running for now and am riding which doesn't seem to bother it. Any idea how the heck I injured the top of my foot?