Chronic low back pain (CLBP) is a multifactorial condition influenced by physical, psychological, and social factors. Conventional physical therapy primarily targets biomechanical impairments, often neglecting psychosocial contributors that perpetuate chronic pain and disability. This randomized comparative clinical trial aims to evaluate the effectiveness of Biopsychosocial (BPS) model-based care versus routine physical therapy on pain, disability, psychosocial outcomes, and inflammatory response among adults with CLBP. A total of \_\_\_ participants with CLBP (≥12 weeks) will be randomly allocated into two groups: Routine Physical Therapy Group - receiving baseline hot pack and TENS, stretching (hamstring, gluteal, iliopsoas, and lumbar extensors), and strengthening/stabilization exercises (planks, abdominal bracing, gluteal isometrics, and bridging). BPS Model-Based Care Group - receiving the same baseline treatment plus Maitland mobilization (Grade I-II central PA), sciatic nerve slider, abdominal bracing, graded functional activity, cognitive behavioral therapy (CBT), pain neuroscience education (PNE), guided imagery, and group-based functional exercise therapy. Primary outcome measures include Pain Self-Efficacy, Oswestry Disability Index (ODI), and C-Reactive Protein (CRP). A secondary variable, Perceived Social Support, will assess the social component of recovery. This study hypothesizes that the BPS model-based care will produce superior improvements in pain self-efficacy, functional disability, and inflammatory markers compared to routine therapy, supporting the integration of biopsychosocial rehabilitation in chronic low back pain management.