There are many diagnoses within the differential of heel pain.  However, plantar fasciitis is one of the most common causes of a stabbing pain in the bottom of the heel, the arch or both areas.  The plantar fascia is a thick, fibrous, ligament-like band on the bottom of the foot supporting the arch of the foot and absorbing shock when you walk.  It is attached to the heel, runs forward along the foot and attaches again at the ball of the foot.  When the plantar fascia becomes irritated and swollen, the condition is called plantar fasciitis.  However, if this progresses to a tear or rupture of the plantar fascia, this is far more serious.

The pain is usually the worst with the first few steps after waking, although it can also be triggered by long periods of standing or when you get up after sitting.  The pain can be worse after exercise, not during it.  This pain can be severe, resulting in a change to your daily activities

Plantar fasciitis can develop without an obvious cause but some factors can increase your risk of developing this condition, including age, some types of exercise, foot mechanics, obesity and often occupations that keep you on your feet.

A podiatrist would initially conduct a biomechanical assessment to try to understand why your plantar fascia is irritated or swollen.  Treatment can involve strapping, strengthening exercises and footwear assessment.  Orthoses may also be recommended.