Low back pain is extremely common. In fact, if you don’t have at least some back pain every year or so, you’re kind of abnormal. (Not that you’re really missing out on anything.) Fortunately, if you do get back pain, your chances of getting rid of it in fairly short order are excellent. More than 90% of acute back pain resolves on its own in just a few weeks or months without any specific intervention. But for some people, pain becomes chronic, lasting for years. Why does the course of back pain differ so much between different people?