Which are signs of kidney stones?

Variable: Some kidney stones are asymptomatic, but even then may cause blood in the urine. If they get large enough and/or cause obstruction in the kidney or ureter (the tube that carries urine to the bladder) they usually cause sudden pain in the back, side, flank or pelvis/genitals, which can be very intense and come in waves. Nausea and vomiting are also often reported and frequent/painful urination.

Renal colic.: Merely having a kidney stone in you will not give you any symptoms. But, if a stone tries to pass and gets stuck, you will get tremendous pain (one of the worst pains known to humankind, actually) and with that pain you will probably vomit and break out in sweats and could even pass out. This is called renal colic.

Here are some...: Glad you had a load of good response detailing wide variation of symptoms related with kidney stone. Urinary stone starts its forming & growing at the tips of collecting tubules at the papillae of renal calyces. As long as attaching to the papillae, it would cause no pain; if detached, it moves & drops into ureter so to pass, if possible, into the bladder. The above process causes its related Sx.