What are aches? Aches are nagging pains. The term aches often evokes the image of muscle pains or joint pains, but any part of the body or organ system may give rise to an ache. Aches may be localized to one area or may be generalized. Aches may range in severity from a minor nuisance to a disabling systemic problem. Aches may have a wide number of causes. Common causes include sprains, strains, arthritis, and overuse injuries. Less common, but more serious, causes include intraabdominal problems, such as appendicitis and hernias; diffuse infections, such as influenza and sepsis; and life-threatening problems such as cancer. The first step in establishing the cause of aches is a physical examination by a doctor. Depending on the doctor’s clinical judgment, further diagnostic testing may be required. This testing might include blood and urine tests; imaging tests, such as X-ray, ultrasound, and CAT scan (also known as CT scan or CT); and specialized testing. In some cases, invasive testing under the care of a specialist may be needed. The treatment of aches depends on their cause. For aches due to overuse injuries or trauma, rest, ice, elevation, and over-the-counter analgesics, such as ibuprofen and acetaminophen, are the mainstays of therapy. More serious causes of aches may require more intensive therapy that is specific to the underlying diagnosis. As with treatment, the prognosis of aches depends on the underlying cause. Seek immediate medical care (call 911) if you have intolerable aches, you experience weakness or paralysis, you have difficulty breathing, or if you have vomiting and fever with a stiff neck. Seek prompt medical care if you have aches lasting longer than three days, if your aches occur after starting a new medication, or if your aches are severe.