I have torn my peroneal tendon. I didn't know it that night. The next morning it was sore. I darn sure knew it the moment I tried to run. Every stride was painful and no amount of stretching and loosening resolved that. It turned out to be a "vertical" tear.

So the good news is that you can run without pain. That doesn't sound like a tear to me. I would take it easy until the pain resides.