How to tell the difference between a kidney stone and lower back pain?

Not always easy: Kidney stone pain is generally unaffected by movement. Patients often bend and twist trying to get relief. Pain often radiates down into groin and may change in nature as the stone moves. Low back pain tends to be associated with an inciting event, tends to change with position and is often relieved by rest. Sometimes radiates to buttock or leg and may be felt across entire back.

Movement: I agree with my colleague above. Also kidney stone patients move restlessly trying to find a comfortable position & frequently have nausea/vomiting. Back pain patients try hard not to move, and nausea is rarely present. Kidney stones can produce blood in urine, while back pain can't.