When stretching the right calve with a straight leg, I get a strange sharp shooting pain down the outer edge of the heel. Almost a tingly sensation. As I ease into the stretch, the pain disappears. Also, if I rub back and forth on the outside of my heel, i can trigger the pain. It's as if some piece of connective tissue is pulling loose from my heel... but dont feel the pain in the actual Achilles. Its just on the outer edge of the achilles/heel. Any idea what this is?