Pain assessment is a complex undertaking that relies on both subjective and objective findings. A thorough pain assessment is the cornerstone to excellent pain management. Further, symptoms associated with pain should be carefully considered by the clinician to determine the source and nature of the pain. Patients who have chronic pain should also be assessed for depression, anxiety, and immobility that can be related to their pain. Patients should also be screened for substance abuse disorder (SUD) or for the risk of relapse if they have a history of SUD. In addition to skillful pain assessment, patient and family support is crucial throughout the patient's illness. This chapter helps nurses to distinguish between acute and chronic pain, identify types of pain according to the description (i.e., somatic, visceral, neuropathic), discuss how chronic pain affects the whole person, and choose tools to determine a patient's risk for opioid misuse.