The plantar fascia is a bow-string like tissue that goes from the heel to the toes. This tissue can become damaged and inflamed in runners, pregnant women, overweight people, and people who lack the appropriate shoe support. Plantar fascitis commonly causes heel pain and may cause increased or stabbing pain first thing in the morning. Heel spurs can be a cause or a side effect of plantar fascitis.

Source: mayoclinic.com