Stretching the calf muscles is recommended in most cases of plantar fasciitis (heel spur). One of my favorite exercises is to use a towel around the arch of my feet and pull towards myself for a few seconds. If it does not increase the pain, stretches can be thirty seconds long, with 15-second breaks, repeated three times with the legs straight (knees not bent). I did this exercise three times a day and often did it while sitting at my desk job.

Too much stretching can re-injure the fascia and cause achilles tendonitis. I would apply ice to the Achilles tendon after stretching if it begins to hurt. Injuring the achilles tendon is serious for those with heel pain because it prevents future stretching. Applying ice to the calf muscle after stretching is recommended by some physical therapists to "preserve the elastic deformation" of the muscle (that is, it's supposed to retain the stretch better).

Below is a picture of stretching using a brick, this method can be very effective but you should proceed with caution.

The calf muscles and fascia can be warmed up in the morning (before walking and stretching) by using a heating pad and/or massaging device, but few will need to go this far. Stretching is more effective when the muscles are warm after activity. There may be benefit to stretching the fascia as well as the calf muscles.

The calf muscle stretch is done by leaning into a wall, is helpful. An alternative method of stretching is to stand approximately two feet from a wall. Facing the wall, turn your feet inward so you are pigeon toed. Lean forward into the wall keeping your heels on the floor and the knees extended. Also keep your back straight and do not bend at the hips. Hold the stretch for 10 seconds and do the stretch ten times in a row. Do the stretching three times each day.