Plantar fasciitis is the term commonly used to refer to heel and arch pain traced to an inflammation on the bottom of the foot. More specifically, plantar fasciitis is an inflammation of the connective tissue, called the plantar fascia, that stretches from the base of the toes, across the arch of the foot, to the point at which it inserts into the heel bone. Overpronation is the most common cause of plantar fasciitis. As the foot rolls inward excessively when walking, it flattens the foot, lengthens the arch, and puts added tension on the plantar fascia. Over time, this causes inflammation.