OK - I am not sure if what I had was similar, but my PT gave me 3 stretches that have helped a bunch and 1 exercise. I am not a PT, and I would suggest you visit one, but these probably can't hurt to try.
First do a normal calf stretch for at least 30 seconds each side. Then add these:
#1 - balls of toes on a curb, off foot down, put a slight bend in your knee on the stretching side. 30 seconds.
#2 - Big Toe Stretch. Cross your legs, barefoot, grab your big toe with one hand and the base of the toe with the other. Pull your big toe back for 30 seconds.
#3 - One foot down, the other on a chair, barefoot, hold your ankle in place and roc forward and backward. This helps increase the flexibility of the ankle. Do this 10 times.
#4 - Lastly an exercise to build a stronger arch. Put a towel on the floor and scrunch it up with your toes, then repeat for 5 minutes each side.
These are hard to explain. so let me know if you have any questions.
JC2