I. Mechanical pain (obstructive pain) Once the stone moves in the body or enters the ureter from the kidney, it becomes blocked at a certain place, causing strong contraction of the ureteral wall and spasm. This kind of colic can be relieved or disappeared by changing position, exercise, etc. Some patients have recurrent attacks. Its duration varies from several minutes to several hours. This type of colic is mainly related to recurrent urinary tract infections and the release of certain bacteria from stones (such as infected stones also called guano stones). Colic is often accompanied by fever or high fever and nausea and vomiting. Its duration can be up to several days. This type of colic is associated with stone obstruction, infection or other diseases. Its recurrent attacks, the time in several days or longer. In summary, renal colic mainly has the above three manifestations. Pain is a reaction to the activity of stones in the body, and the degree of pain varies greatly among individuals due to many reasons (in mild cases, only pain in the lower back and abdomen; in severe cases, pain in the lower back and abdomen is like a knife, and in a few patients, colic can lead to shock). Clinically, pain due to kidney stones is rare; the majority of pain is caused by obstruction when the stones are in the three narrow parts of the ureter. In fact, in the management of stone disease, it is often good to have pain. The stone can be removed from the body. The stone is cured and the pain disappears. Conversely, the absence of pain (i.e., asymptomatic stones) does not attract attention and treatment. In the long run, it will cause more damage to the tissues, organs and body. In severe cases, it may even endanger life.