Metatarsalgia is the term used to describe pain and inflammation that occurs under the ball of the foot.  Metatarsals are the five long bones in the foot that end at the ball.  When the metatarsals drop or are subject to excess pressure (such as when one wears high heeled or ill-fitting  shoes) they can become sore and inflamed.  See your doctor for a proper diagnosis.

Treatment may include rest, icing, proper foot wear and sometimes foot orthoses (insoles).  A rockered soled shoe often works to reduce pressure at the metatarsal area and reduces further injury.