A nurse is conducting a pain assessment for a client who reports discomfort. Which of the following actions is the most appropriate for the nurse to take to obtain a comprehensive understanding of the client's pain?

Observe the patient's facial expressions and body language for signs of discomfort.

Measure the patient's vital signs and note any changes.

Review the patient's medical history for past pain management interventions and their outcomes.

Ask the patient to describe the pain using a pain scale and provide details about its location, duration, and intensity.