What is back pain? Back pain is any type of pain or discomfort throughout the posterior (back) portion of your trunk, from the pelvis up through the neck. Back pain is a very common problem in the United States, second only to headache, according to the National Institute of Neurological Disorders and Stroke. Your back pain may last briefly or it may be chronic, which is defined as lasting more than three months. Back pain may be described as a dull, annoying ache or a sharp, acute pain. Acute back pain often resolves with basic self-care measures within a few weeks, but it can persist and lead to more serious problems over time. The back consists of the spine (spinal column), spinal cord, nerves, discs, muscles, ligaments, and tendons. Any of the structures in the back can become irritated or inflamed in response to a variety of mild to serious conditions. Reasons for back pain include sports injuries, poor posture, arthritis, muscle strain, and trauma suffered from a car accident. The origin and cause of chronic back pain is harder to diagnose and treat. Back pain may be localized to a specific area, such as lower back pain, or it may cover a more generalized section of the back. In addition, localized pain anywhere in the back can radiate, or spread, to other areas of your body. The converse is also true; pain somewhere else in your body can radiate to your back. Back pain accompanied by other symptoms, such as loss of bladder or bowel control and numbness in your extremities (arms or legs), is a serious condition and should be evaluated as soon as possible or in an emergency medical setting. In addition, if your pain is extreme, persistent, or causes you concern, contact a medical professional.