Whereas temperature, pulse, respirations, and blood pressure are all objectively measured, pain is inherently subjective. Given this fundamental difficulty, it is no wonder that failure to properly assess pain is a common cause of its poor control and lack of treatment in patients in different settings (1). Moreover, pain is multidimensional, with "sensory-discriminatory, cognitive-evaluative, and affective-motivational" components (2), or in other words, it affects body, mind, and spirit, and its complexity makes it hard to measure (1). Since pain has been recognized as an important modality, influencing recovery and quality of life in patients, it has been termed "the fifth vital sign" and is now being evaluated and registered in the patients' charts during routine checkups. Pain itself is repeatedly rated by the patients and the caregivers or the medical personnel, it is followed and treated.