Kidney stones are hard crystals that form inside the kidney. When they shift or try to leave, they send out sharp, clear warnings.

The star symptom is sudden, severe flank pain. It feels like a knife below the ribs and shoots into the groin as the stone moves.

Nausea and vomiting often follow. The pain triggers a sick stomach, even though the gut is fine.

Blood in the urine is common. The stream may look pink, brown, or tea-colored, and the change can appear even when pain is mild.

Urinary urgency shows up next. You race to the bathroom every few minutes, pass only drops, and feel burning like hot sauce.

Some people see tiny gravel or grain-like bits in the urine once the stone starts to break apart.

If infection sets in, fever, chills, and cloudy urine join the mix—an emergency signal that the stone has become a germ trap.