Heel Spurs or Calcaneal Spurs are often present with Plantar Fasciitis.  However, you can have Plantar Fasciitis without a heel spur being present.  A heel spur is caused by repeated strains on foot muscles and ligaments which cause stretching of the plantar fascia and repeated tearing of the membrane that covers the heel bone.  This leads to a build up of calcium deposits under the heel that over a period of time, develop into a spur.   It is this spur that protrudes into the surrounding tissue that gives rise to sharp pain on every step that you take.  

Heel Spurs are really common in sports that involve large amounts of running and jumping. Most people that are in occupations where they are on their feet for the majority of the day can also be predisposed to heel spurs.