Plantar Fasciitis is when you feel pain along your heel or foot especially when you're walking or climbing stairs. It can be caused by having flat feet, poor walking/running mechanics, high arches, and certain activities such as being a long distance runner.
There are several things that help, such as having proper foot wear, orthotics, proper running mechanics, as well as some self myofascial release, stretches and exercises you can do.

1. Trigger Point: you can roll the bottom of your feet, this can actually aggrevate some cases so be careful. Roll along the bottom 30-60s at each point of discomfort.
Calves are important to foam roll as well, they can be tight and will pull the muscle of the foot. Find points along calf and hold down for 30-60s
2. Stretches: These are pictures here, first is a stretch for the toes hold for 30s.
 Next up for the whole bottom of the foot.
 Use a towel and pull toes towards face, hold for 30s. Last for the calves, any calve stretch will work, I just like this one, feet split position, bend into front leg and keep back foot on the ground flat, should feel it in the back leg.
3. Exercises: Pebble drop, using just your toes to pick up bring a marble or pebble from one place to another , repeat 10x 2-3sets.
Towel scrunches, have towel on ground use toes to scrunch it and pull it towards you.