Body aches and flu: what should you know?

Flu can trigger inflammation throughout the body, which makes muscles feel sore or heavy. Aches may begin quickly and affect the back, arms, legs, or several areas at once. Other infections can produce a similar pattern, including COVID-19, dengue fever, malaria, or brucellosis. Aches that continue after an infection, especially with marked fatigue, can also occur with Long COVID. Longer-lasting widespread pain has different possible explanations, including fibromyalgia or an underactive thyroid. The pattern, travel history, temperature, and other symptoms help a clinician narrow the cause.

Rest, drink fluids regularly, and choose light meals if your stomach feels unsettled. Gentle movement can reduce stiffness, but stop if it worsens the pain. Follow the label when using a fever or pain medicine, and check with a pharmacist if you are pregnant, have liver or kidney disease, take regular medicines, or are considering combining products. Stay home while you feel acutely unwell and reduce close contact with others. If symptoms started recently or you have a long-term condition, ask a clinician whether testing or early treatment is appropriate.

Seek urgent medical help for trouble breathing, chest pain, confusion, fainting, severe weakness, a stiff neck, or inability to keep fluids down. Arrange prompt assessment for a very high or persistent fever, worsening symptoms after initial improvement, a new rash with fever, yellowing of the eyes, or illness after travel to a malaria-risk area. Contact a clinician if aches do not start easing, keep returning, or interfere with normal activity.

Could this be influenza or another infection, and would testing change my care? Which pain or fever medicines fit my health history? What warning signs should prompt urgent help?