Back pain generally can be classified into one of two categories:

• Acute. Short-term pain that generally lasts for a few days or weeks before subsiding. Most acute back pain results from an injury or trauma to the lower back, or a flare-up of a disorder such as arthritis. Symptoms of acute back pain include muscle spasms and aches, shooting or stabbing pains, limited flexibility and range of motion or an inability to stand straight. In some cases, pain felt in one part of the body may radiate from a disorder or injury located elsewhere in the body. Left untreated, some forms of acute back pain can become more serious and chronic.
  
  
• Chronic. Often defined as pain that lasts for more than three months, or longer than is expected for the condition causing the pain. It is frequently progressive, with pain increasing over a period of time. In many cases, the cause of chronic back pain can be difficult to determine as pain can persist even though the underlying condition has healed.