Plantar fasciitis is painful inflammation of the thick, fibrous band of tissue that reaches from the heel to the toes, supporting the muscles at the bottom of the foot. When the plantar fascia becomes overly stretched, tiny tears can riddle its surface. This condition is more common in women than men. You are also more likely to suffer from plantar fasciitis as you get older, or if you:

• are overweight.
• are on your feet for hours and hours each day.
• have other conditions such as rheumatoid arthritis or lupus.
• tend to wear high-heeled shoes, then switch abruptly to flat shoes.
• wear shoes that are worn-out, with weak arch supports and thin soles.
• have flat feet, legs of uneven lengths, an unusually high arch, or an abnormal gait.

Source: WebMD®