I have the same issue. Just started recently (about 3 weeks ago). It happens maybe once or twice every 3-5 days, and lasts for like 10 seconds. So, it doesn't happen often enough that I've been concerned yet. But it seems to be something regularly occurring now. But to your point it's definitely VERY sharp and hurts a lot. When it happens, it comes on IMMEDIATELY and causes me to actually grab my foot quickly.
I do play a lot of soccer, but it has not been a problem while playing or even after. It has seemingly happened not even anywhere close to when I have played soccer. Just now it happened (Friday), but last I played soccer was Tuesday.
I also don't think I injured it, but certainly the stress of running could be part of the issue.
I'm not on Prozac or anything, so can't talk to that. But I did recently take a strong pain med (anti-inflamatory) for a painful back injury (of course from soccer). That was one a day for 2 weeks. Pain is gone. I haven't taken the meds in like 2 weeks. But wonder if my body got used to getting anti-inflamatories and now something is happening.
Keep me updated. I'll do the same. Hopefully someone else has an answer here. Otherwise if it keeps happening I'll go see a podiatrist.