One cause of<unk>  is Morton's neuroma. When toes are squeezed together too often and for too long, the nerve that runs between the toes can swell and get thicker. This swelling can make it painful when walking on that foot. High-heeled, tight, or narrow shoes can make pain worse. This is common in runners, particularly of long distance. The ball of the foot takes a lot of weight over the years and if running on pavement or running in ill-fitting running shoes, the odds of developing Morton's neuroma increase. Changing to shoes that give the toes more room can help.
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