Plantar Fasciitis: Inflammation of the plantar fascia (fibrous connective tissue on the bottom of the foot) is referred to as plantar fasciitis. Causes may include injury, arthritis, ankylosing spondylitis, and diffuse idiopathic skeletal hyperostosis. Symptoms sharp, severe foot and heel pain, difficulty bearing weight on the foot, difficulty walking especially in the morning, and swelling. Treatment may involve orthotics, cortisone injections, physical therapy, or medication.