It is sometimes hard to tell the difference between back pain that is caused by a bone or muscle problem and back pain (flank pain) that is caused by a kidney or bladder infection or a kidney stone.

Back pain that is caused by a bone or muscle problem:

• Occurs in the lower back; below the waist; or in the upper back, over the spine or between the shoulder blades.
• Gets worse when a person moves.
• Gets better when a person rests.

Flank pain that is caused by a kidney infection or a kidney stone:

• Is pain felt just below the rib cage and above the waist. Flank pain can be on one or both sides of the back.
• May spread to the bladder area or genitals.
• Gets worse as the bladder fills.
• Does not get worse when a person moves.

Flank pain with fever and urinary symptoms may mean a kidney infection (pyelonephritis) is present.