Pain in the ball of the foot is called metatarsalgia and may have many different causes (including arthritis, pinching of the nerves between the toes, posture problems, and various disorders).
The most common causes include
Age-related thinning of the fat pad cushion in the ball of the foot
Often, developing one disorder that causes pain in the ball of the foot contributes to development of another disorder that causes pain in the same location.
(See also Overview of Foot Problems Overview of Foot and Ankle Problems Some foot problems start in the foot itself, for example, resulting from a foot injury. Problems can occur in any bone, joint, muscle, tendon, or ligament of the foot. Foot and ankle fractures... read more .)