Sharp foot pain

Hello,

After my run on monday, I got a sharp pain in the outside of my right foot. It is right behind the toe joint of my pinkie toe. I haven't run since then, but it's still bothering me walking around on it. It only hurts when weight or pressure is applied, and it is fairly localized. It's not a specific point, but a fairly small area, maybe the size of a couple of finger tips. I run in vibram five fingers, and have for about a year. I was wondering if anyone might have any ideas as to what it might be? It onset after one specific run, and it wasn't anything more than I usually do. The run was over a mix of pavement and gravel/dirt type trails. Since the shoes are so minimalist, I was thinking it might be as simple as I stepped on a rock or something like that and gave myself a really good bruise, maybe even a bone bruise, but I don't remember specifically stepping on anything. There isn't any swelling or visible bruising, but I have always tended to not show bruises very much. Moving my foot does not affect the pain at all, it's only when walking (and presumably running) when that part of my foot bears weight and a little bit if I press firmly on it. Any ideas? Thanks