I had PTTD surgery and had my heel bone shifted during it, which realigned my foot. My foot was pretty badly pronated for a long time prior to surgery. When the foot is put into proper alignment the peroneals are at risk as they are stretched tighter than they were. In a perfect world they adapt and all is well. But I had an overzealous physical therapist that was trying to force my foot into inversion by manually jerking it inward. I'm convinced that is what tore the peroneals as it was excrutiatingly painful when he did it and that pain never went away until after surgery.
The pain was behind my ankle bone and sort of felt like it was underneath the ankle bone too...deep inside. I also had some snapping of the tendon from time to time which is what first clued my doctor into the fact that it may be something else going on besides PTT surgery recovery. So, one year after reconstruction I had the peroneals repaired. By the way, the MRI only showed one was torn but when he got in there they both were.
Hang in there. Hope you feel better soon.