Kidney stones may remain in your kidneys causing no symptoms. However if a stone begins to move out of your kidneys it can be painful or block the passage of urine and you may need treatment.
Your kidneys are a filter for your body-removing waste chemicals and excess fluid from your blood by making urine. Most waste dissolves in your urine and passes from your body unnoticed. However if there is a build-up of chemicals, tiny crystals can form. Several crystals can clump together to form a kidney stone.