To the OP: if you haven't gotten around to seeing a doc or PT yet, you should at the very least get to stretching your calves, asap. On top of that, the leaning towers calf exercise can help strengthen the calf and improve stability in the foot. To perform a leaning tower, keep your feet flat on the ground, hip width apart, toes forward... lean forward with your legs and body straight, only as far as you can while keeping your heels firmly flat on the ground, and then pull yourself back to upright using your calves and feet.
I'd shy away from the inserts as well unless they've been prescribed by a podiatrist or a PT. Sometimes they can cause more harm than good.