When the word is broken down, neuroma means 'tumor of a nerve.'  A neuroma is essentially a nerve that has become inflamed and often has built up scar tissue, giving it the gross appearance of a mass of tissue (or a tumor).  In the foot, this most commonly occurs between the 3rd and 4th toes at an area where two nerves have met and then split to provide sensation to adjacent sides of the toes.  This area of the foot can be a pretty tight space in certain people, and if shoes are too narrow to allow the bones to spread and give the nerve room, it becomes inflamed and develops scar tissue.  This scar tissue feels like a lump and can give the sensations of burning, tingling or even numbness to the affected area and the sides of the toes.