Is this painful bump a fibular stress fracture or stress reaction?

Today's episode comes from a question that was posted as a comment on one of the videos on the Doc On The Run YouTube channel about the difference between a stress reaction and stress fracture in the fibula in runners. 

He said:

“Hey, I really appreciate the video, I go to the gym a lot and I was doing the treadmill at maximum speed and one day my fibula started hurting a lot after the gym in the lower leg on the outside and I found out it was my fibula. I took a day of rest and went back to the gym, and I was running on the treadmill even when my leg was hurting.”

What is this painful bump that might be a fibular stress fracture? 

Well, that is what we're talking about today on the Doc On The Run Podcast.