I had the same problem - and it still comes and goes.
The podietrist (?sp) showed me how to do a really deep stretch - like doing a lunge, only use the wall to support yourself and get that pull in your calf. Strangly, when the calf is tight, your feet will suffer. I often use a countertop to lean against and try to get as good of a stretch in the back calf. Then do the other side. Watch out when starting this, i pulled something initially (I think I was already injured) and it was hard to do the stretch too deep. Work in to it slowly.
Play around with your posture to ensure you strech the whole calf. Hold in one position, then maybe move your leg back a little more and see if you get more of a stretch.
**