Metatarsalgia is pain in the ball of the foot caused by pressure on the metatarsal bones from high-impact activities, poorly fitting shoes, arthritis, or structural foot issues. Common causes include running or tennis which increase pressure, wearing high heels or restrictive shoes, being overweight, and foot conditions like bunions. Treatment focuses on resting the feet, using ice, wearing supportive shoes, and using metatarsal pads to reduce pressure and pain.