6 years is well outside the time limit you can expect an orthoses to last. The simple 'formthotic' will last around 6 months and a casted orthoses generally will do max of 2 years. So I suspect that you have long since worn through your previous orthoses. The stretching you'd be advised to do are the long and short calf stretches. Google them and do them twice a day. Stretch for 30 seconds and DON'T overstreatch or you will aggrivate the condition. If you feel pain your going too far, you should feel stretch before pain if you feel pain before stretch don't push any further into the range over the 30 seconds