The overarching goal of this study phase, Phase II component is to perform a randomized clinical trial of the refined Computerized Chemosensory-Based Orbitofrontal Networks Training for Treatment of Pain \[CBOT-Pain (or CBOT-P)\] from Phase I, compared to sham Computerized Chemosensory-Based Orbitofrontal Networks Training (CBOT) in Chronic Low Back Pain (CLBP) to determine its short- and long-term effectiveness on Pain, Negative Affect (NA), Cognition and Cortical Brain Structure (PACS), long-term safety, and indications. The investigators will perform a randomized clinical trial of the refined CBOT-P from Phase I, compared to sham CBOT in CLBP. Aim 2.1: To determine if CBOT-P significantly influences: (1) acute and long-term reduction of pain severity, and (2) acute and long-term reduction of negative affect. The hypothesis is that optimized CBOT will produce faster, stronger, and longer-lasting improvements in pain severity, NA severity, cognitive impairments, and sleep and functional outcomes. Aim 2.2 To determine if CBOT-P significantly prevents or reduces progressive shrinkage in the orbitofrontal cortex (OFC), cingulate cortex, and hippocampus. MRI will be acquired at baseline and 6th month. An integrative analysis will be conducted to determine the link between changes in brain structure and cognitive trajectory. The hypothesis is that the CBOT optimized with BCP significantly attenuates shrinkage in OFC and other prefrontal cortex (PFC) regions, compared to the Sham intervention.