Plantar fasciitis is the term for heel and arch pain due to inflammation and strain of the plantar fascia. This thick band of tissue starts at the heel bone, runs across the arch of the foot, and attaches to the base of the toes. Its purpose is to support the arch of the foot. Often, plantar fasciitis is characterized by increased pain after a period of rest—for example, during your first steps upon waking up. This occurs because putting your full weight on your bare foot damages and tears the fibers of the plantar fascia.