Corns occur when toes rub against each other or skin is squeezed between your shoe and the bones of your feet. They can be hard or soft and although painful, options are available to ease the discomfort.
Corns are often caused by footwear, so try to ensure your shoes are comfortable and give your toes room to wiggle about. Other problems, such as how you walk, can also cause them. If corns keep appearing it's worth speaking to your GP, Podiatrist or Pharmacist.