Why does my lower back hurt when I have a fever?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Lower back pain with a fever is a common symptom combination, often caused by your body's inflammatory response to an infection. In some cases, the pain may signal an infection directly affecting the back, such as a kidney infection (pyelonephritis), spinal infection, or urinary tract infection that has spread. Viral illnesses like the flu can also trigger widespread muscle aches, including in the lower back.

Because the underlying causes range from mild to serious, it's important not to guess. A free, instant, online symptom check can help you quickly identify possible causes based on your specific symptoms and guide you on whether to rest at home, see a doctor, or seek urgent care. Taking a few minutes now could save you time, worry, and potential complications later.

Reviewed for medical accuracy: 07/14/2026

Important Next Steps

Learn likely causes of fever and back pain See if fever and back pain need care Find out if fever and back pain signal infection Discover over-the-counter relief for fever and back pain Find a doctor for fever and back pain Understand home remedies for fever and back pain Check symptoms to assess fever and back pain

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Explanation

Low back pain with fever happens as a result of two main reasons:

Immune response of the body

When the body is fighting infections such as bacteria and viruses, it is in a state of inflammation. The inflammatory response leads to a release of substances in the body that causes fever, chills, headache, joint pains and muscle aches. The muscles that support the spine and hips are some of the largest in the body so naturally these muscles will often ache the most.

Symptoms of the infection itself

Sometimes pain in the back with fever can be due to an infection in the back itself. Several structures, like the muscles, joints of the spine, and discs between the spinal bones can actually become infected themselves. Additionally, urinary tract infections or kidney infections can lead to back pain and fever. If you're experiencing these symptoms, use our free AI symptom checker to help identify what might be causing your discomfort and determine if you need medical attention.

(References)

Medappil N, Adiga P. A 31-year-old female with fever and back pain. J Emerg Trauma Shock. 2011 Jul;4(3):385-8. doi: 10.4103/0974-2700.83869. PMID: 21887031; PMCID: PMC3162710.
Cameron CR, Burgess CD. Recurrent back pain and fevers. Med J Aust. 2007 Feb 19;186(4):208-9. doi: 10.5694/j.1326-5377.2007.tb00864.x. PMID: 17309425.
Bernheim HA, Block LH, Atkins E. Fever: pathogenesis, pathophysiology, and purpose. Ann Intern Med. 1979 Aug;91(2):261-70. doi: 10.7326/0003-4819-91-2-261. PMID: 223485.

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