If you have pain on the bottom of your heel and feet when you walkor run, you may be suffering from plantar fasciitis. Plantar fasciitis is pain and inflammation of a thick band of tissue on the bottom of the foot. The plantar fascia is a common area for problems because you are standing, walking and running on it all the time, especially if you're an athlete. This repetitive stress leads to micro tears, swelling and nerve irritation that cause pain. Plantar fasciitis is common in runners, people who are overweight, people who are on their feet for long periods, pregnant women and people who wear shoes with inadequate support. Plantar fasciitis, if left untreated can lead to foot, knee, hip and back pain due to the changes in the way you walk.