Pain at Very Bottom of Calf

So I’ve had chronically sore Achilles tendons for a couple years, I just have to stretch them out before athletic activities. If anyone has advice on how to fix that I’d love to hear it; I tried extra direct calf work, less calf work, no calf work, stretching, rest. But I digress, that’s not why I’m posting today.

I’m posting because today while at the track I was warming up for some sprints and doing a 1/4 speed run when I felt this really bad pain at the bottom of my left calf. My first thought was “oh fuck I tore my Achilles”, then I realized I could still move my foot fine. I just can’t really bear full weight on my left leg because the very bottom part of my calf experiences this really bad pain/soreness/tightness/stiffness. It’s not really sharp, just…hurts. Any ideas on how to fix it? I don’t think anything is torn, I can still flex the calf, and like I said my foot’s range of motion isn’t impeded.