Investigators will conduct a moderate-term, double-blind, randomized controlled trial, and use quantitative sensory testing (QST) to evaluate whether changes in pain sensitivity and pain modulation occur as a result of long-term opioid use. Investigators hypothesize that increases in pain sensitivity (i.e., OIH) and maladaptive changes in endogenous pain modulation (i.e., enhanced temporal summation of pain) will occur as a result of long-term opioid use, but that these changes will be observed predominantly among patients with high levels of negative affect and pain-related catastrophizing.