Kidney Pain

Pain caused by the kidneys is typically felt in the flank area, which is in the back, just at the lower edge of the ribs on either side of the spine. Pain caused by the kidneys tends to be sharp, severe and occur in waves.
What Isn't Kidney Pain
It is rare for the kidneys to cause dull, aching pain. People sometimes equate back pain with kidney pain, but dull aching pain in the back -- especially the lower back or the middle of the back -- is usually due to muscles, ligaments, or even vertebrae and disks in the spinal column. Musculoskeletal pain typically gets worse with movement, and is relieved by heat or massage.
Common Causes of Kidney Pain

Kidney Stones
Cause of Pain: The pain caused by kidney stones occurs when a stone becomes lodged in the ureter, the slender tube that connects the kidney with the bladder. Urine flow is then blocked, which causes urine to back up into the kidney. The kidney then swells and enlarges, stretching the pain-sensitive capsule, or thin covering around it.
What to expect: The pain caused by kidney stones is referred to as "colic," meaning that it comes on in waves as opposed to being a steady continuous pain. Pain from kidney stones is described as being almost as severe as that of childbirth. Patients with renal colic usually find it very difficult to hold still, and are in constant motion, pacing and writhing. Often the pain is so severe that it causes nausea and vomiting.
Although the pain starts in the right or left flank area, it may move as the stone travels down the ureter. The pain may move around the side of the trunk to the lower part of the abdomen in the front and even travel down to the groin.