How do you determine what to do with a very mild injury?

I have recently started running longer distances more often and on hillier terrain with the intention of running my first race (5 miles) on Thanksgiving Day.

I have never been an athletic person and don’t know the first thing about sports or training. I often get little aches and pains but they always go away after a while so I’ve learned to just ignore them.

Recently I’ve gotten a new one, and I thought it was in my ankle but now I think the actual source of the pain is in my foot itself. It is definitely bearable and I can easily run on it, but every time I ignore one of these little pains I have this nagging worry that I’m going to keep making it worse and worse until I’m forced to stop running for a while. And I definitely don’t want that to happen between now and Thanksgiving!

I guess the safe answer would be to always consult a doctor, but that’s not very efficient, especially considering that so far none of these little pains have amounted to anything. So is there a good heuristic for deciding if sports-based pain is the good kind of pain (weakness leaving your body) or the bad kind (wreaking havoc on your body)?