kidney stone :
Kidney stones or renal calculi are hardened deposits of salts and minerals that form in the kidneys. Small sized kidney stones generally pass out along with urine. However, when these are larger in size, they can cause abdominal pain or pain in the sides, back, or below the ribs.
You should immediately consult a doctor if you are unable to sit in a comfortable position, suffer from fever, chills, nausea, and vomiting.