Q. What’s the difference between chronic and acute pain?

A. Chronic pain is pain that lasts longer than three months. Acute pain is pain that’s been present for less than three months. Of course, some pain disorders don’t fit neatly into those categories. For example, you could have a migraine for one week of every month and it could go on for 30 years. The psychological impact of daily back pain that ranks 4 on a 1-to-10 pain scale could be much greater than headache pain that ranks 10 for just two days each month. Having pain all day every day can wear you down emotionally. We don’t see that happening as much with acute pain.