Sat Nam,
Plantar fasciitis is most commonly caused by either hyperpronation (flat feet), hypersupination (high arches), or excess body weight increasing the load on the plantar fascia. Hyperpronation of the foot is when the inside of the ankle rolls towards the ground, the front foot toes-out, the leg rotates inwards in relation to the foot, and the foot points up towards the sky. Hypersupination of the foot is when the outside of the ankle rolls towards the ground, the front foot toes-in, and the foot points down towards the ground.
The exercises in these links can help you release the pain that plantar foot causes
http://s3cr3ty0stg2.wpengine.com/hatha-yoga/eagle-garudasana.html
http://s3cr3ty0stg2.wpengine.com/hatha-yoga/downward-facing2.html
Blessings