This usually happens to people who are very active such as runners or hikers.  The tissue at the bottom of your foot, under the skin, is called fascia.  Due to repetitive micro trauma your fascia can accumulate adhesions (or knots) that begin to tighten the fascia and pull on your heel (sometimes causing heel spurs).  This tissue can become inflamed and very painful. By realigning the bones in the foot and breaking up the adhesions, Plantar Fasciitis is usually easy to treat and gets you feeling pain-free.