Inclusion Criteria:  Intact cognitive status and ability to provide informed consent Ability to read and write in English sufficiently to understand and complete study questionnaires (which are only validated in English) Age 18 or older And Presence of persistent daily low back pain of at least three months duration and of at least a 3/10 in average intensity  Exclusion Criteria:  History of renal or hepatic dysfunction Reports of current or past alcohol or substance abuse or treatment for such condition A reported history of PTSD, psychotic, or bipolar disorders Chronic pain due to malignancy (e.g., cancer) or autoimmune disorders (e.g., rheumatoid arthritis, lupus) Reports of recent benzodiazepine use (confirmed via rapid urine screening prior to each lab session) Any medical conditions (e.g., significant cardiovascular disease) that the study physician feels would contraindicate participation in the lab stressors Reported daily opiate use within the past 6 months, or use of any opioid analgesic medications within 3 days of study participation (confirmed through rapid urine screening prior to each lab session) Pregnancy (females only, to avoid fetal drug exposure - pregnancy tests conducted prior to each lab session to confirm eligibility) Prior allergic reaction/intolerance to oxycodone or its analogs