Plantar fasciitis is irritation of the thick band of tissue that runs along the bottom of the foot, from the heel to the toes. The classic sign is sharp heel pain with your first steps in the morning or after sitting, which often eases as you move and then returns later in the day. It usually develops from a mix of factors such as foot mechanics, footwear, a change in activity, and tightness through the calf and lower leg. Care focuses on calming the irritated tissue, addressing what is overloading it, and getting you back to comfortable, pain-free steps.