What does it feel like? For me, it feels kind of like Plantar Fasciitis. A dull ache in the arch of the foot. The pain is mostly on the outside of the arch, halfway between the toe and the heel. The peroneal tendon comes down around the ankle and attaches to the bottom of the foot in that area.
Google it for more info.
I can run fine for several miles. Then it gets angry. If I'm running on uneven terrain, it gets worse.
NSAIDs are very effective. But at what cost? I did get a prescription for a Ketoprofen cream (basically an NSAID that you rub on the affected area). It works too. But my insurance doesn't cover it, and it is about $40 per ounce. That should last me a couple weeks, and with the allowable refills, I will definitely have some magic cream in my next 100 miler drop bag.
Rest is working for me. I'm hitting the weights and relaxing. It's nice to end the summer knowing that I don't have to run 100 miles anytime soon.
But then again, MMTR is just around the corner.