To stretch, soften and relieve tension in the connective tissue on the sole of the foot/heel.
Be seated in a chair. Place either a firm foam roller of 3-6 or just an ordinary sized can of food, or a tennis ball, beneath the sole of the affected foot.
Slowly and in a controlled manner, apply some downward pressure into the roller or can and simply roll back and forth to massage and stretch the sole of the foot.
Use your own intuition as to where the tightest areas are. If an area is particularly tight or sore, pause in that area for 10-15 seconds before moving on.
Other items may be used such as a cricket ball, or a golf ball as well as a rolling pin.