I suffer terribly from kidney stones and have had episodes of excruciating pain associated with them. These episodes can last for hours. I recently had an ultrasound lithotripsy which is a procedure to break up stones in the kidney using sound waves. As a result I have been passing fragments of stone that are too small to cause pain or even any sensation whatever. However, two of the larger fragments passed with a sensation that is like pain. I wonder if there is a medical term for what I experienced. That is, the exact same sensation, the same nerves, the same mental construction as the most excruciating stone pain. The similarity to stone pain is undeniable. Yet it is so subtle as to be just above the threshold of sensation and duration less than a second. Pain doesn't seem to be the right word to express a sensation that isn't painful at all.