Which of the following is NOT an example of acute pain?

Acute pain is typically defined as pain that occurs suddenly and is usually associated with a specific injury or illness. It serves a biological purpose, alerting the body to potential harm and facilitating healing. In this context, chronic back pain does not fit into the category of acute pain because it persists over a long duration, often lasting for months or even years, and is usually due to underlying conditions rather than a specific, short-term injury.

In contrast, the other examples—such as injury, post-operative flare, and burn from a hot surface—represent situations where pain is acute, arising from an identifiable source and typically resolving as the underlying issue heals. Thus, understanding these definitions helps clarify why chronic back pain is distinctly categorized separate from acute pain scenarios.