After a prolonged abdominal surgery, a patient reports persistent lower back pain. What is the immediate action you should take?

The most appropriate immediate action in this scenario is to inspect the patient's lower back. After a prolonged abdominal surgery, it is crucial to assess the site of discomfort for any signs of complications such as hematomas, infections, or issues related to surgical manipulation. This physical assessment will provide valuable information regarding the nature of the pain and whether it might be related to a post-operative complication.

While administering pain medication and documenting the pain are also important actions, they should come after ensuring that there are no serious underlying issues causing the pain. Changing the patient's position can sometimes alleviate discomfort; however, it does not provide direct information on the cause of the pain. Therefore, thorough inspection of the area is the best first step in addressing the reported lower back pain effectively and safely.