Most ordinary back pain does not cause a fever. When back pain occurs together with a fever, it raises concern for an infection that needs prompt medical attention. Possible causes include a kidney infection (often with pain in the side or lower back, painful urination, and feeling unwell), or, less commonly, an infection of the spine itself or the discs between the vertebrae.
Spinal infections are more likely in people with weakened immune systems, diabetes, recent spinal procedures, or a history of injecting drug use, and they can cause lasting damage if not treated quickly. An abscess near the spine can also press on nerves.
Seek urgent medical care if you have back pain with a fever, chills, severe or worsening pain, night pain, painful or bloody urination, numbness or weakness in the legs, or loss of bladder or bowel control. Call your local emergency number for severe symptoms. Early diagnosis and treatment, often with antibiotics, are important.