A 48-year-old white man presents to the emergency department with unremitting right flank pain. He denies dysuria or fever. He does report significant nausea without vomiting. He has never experienced anything like this before. On examination, he is afebrile, and his blood pressure is 160/80 mm Hg with a pulse rate of 110/min. He is writhing on the gurney, unable to find a comfortable position. His right flank is mildly tender to palpation, and abdominal examination is benign. Urinalysis is significant for 1+ blood, and microscopy reveals 10–20 red blood cells per high-power field. Nephrolithiasis is suspected, and the patient is intravenously hydrated and given pain medication with temporary relief.What is the cause and pathogenesis of kidney stone disease? Why are kidney stones painful?