when i was in the marines i was bothered with them and later racing i had the same problem, ice and an anti inflamatory (advil , motrin) help relieve the pain, i did some reading on this problem and the backwards runing thing is very close to the cure, your calf muscles in the back are so much stronger than the ones in front that you actually overwork the ones in front, standing with your heal on a board or a brick and doing toe raises to stenghten these muscles and reduce the tearing seems to be the fix, add this to your stretching and it should be gone, the running backwards works the same way you pull your toes up as you step back making these muscles work more , it doesnt take muck excersize at all to make these small muscles quit hurting, but they have to be included in a small way.