When a muscle spasm is severe and lasts for an extended period of time, trigger points can develop, especially in areas where the muscle is under enormous pressure. Trigger points, called “ouch points” in Chinese medicine, occur where there is an accumulation of lactic acid trapped in a consolidated area of the muscle. When a muscle burns energy, it makes lactic acid as a waste product that under normal circumstances gets flushed out and carried out of the body through urine. When the muscle is under constant tension, it is producing elevated amounts of lactic acid, in turn making it harder for the body to dispose of it. Trigger points can be felt in muscles as tender, dense rounded bumps, ranging from very small to the size of a grapefruit. It is not surprising that when a waste product gets stuck in muscle tissue, it becomes an irritant and generally results in inflammation.