A Morton's neuroma is a painful swelling in the nerves traveling into the front half of the foot and toes.  It causes pain with tight shoes or when pressure is applied to the ball of the foot. It may feel like a pebble in your shoes or a sharp pain going into the toes.  Sometimes the affected toes will be numb. 

A simple shoe insert may help, along with medication.  Injections also work and surgery to remove the neuroma is helpful for those that continue to have pain.