A hypersecretory tumor of parathyroid gland leads to the hypersecretion of parathyroid hormone (PTH). The tumor will produce more than the normal amount of PTH. The hormone controls the concentration of calcium in the blood. PTH causes the release of calcium from bones increasing calcium concentration in the blood. As kidneys filter blood and excrete the excess of calcium from the blood, the concentration of calcium in the urine will increase in patients with parathyroid gland tumor. This process will lead to the formation of kidney stones associated with painful symptoms.