This study looks at the non-invasive brain stimulation technique in people with chronic low back pain to see: * How effective non-invasive brain stimulation is at improving pain intensity in people with chronic low back pain? * How safe non-invasive brain stimulation is and what side effects there may be? * What study participants think of the study procedures and of the non-invasive brain stimulation as a treatment technique for chronic low back pain. Participants will be assigned to receive either active brain stimulation group or sham stimulation group randomly. Participants will be required to attend a total of twelve treatment sessions (approximately 1-hour each, three sessions per week, for four consecutive weeks). Assessments will be done at baseline (in the week 0), immediately post-completion of the intervention (in the week 5), and at the follow-up of one-month (in the week 8), three-months (in the week 16) and six-months (in the week 28) post-completion of intervention.
Inclusion Criteria: * Age between 18 to 75 years on the day of screening * Pain in the lower back (region between 12th rib and gluteal fold) with or without accompanying leg pain that occurs for at least half the days in the last six months * An average pain intensity of ≥4 on the 11-point NPRS (0=No pain to 10=Pain as bad as you can imagine) in the week prior to enrolment * A disability score of ≥5 on Roland-Morris Disability Questionnaire (RMDQ). Exclusion Criteria: * Known or suspected serious spinal pathology (fracture; lumbar canal stenosis, malignant, inflammatory or infective diseases of the spine; cauda equina syndrome or widespread neurological disorder) * Suspected or confirmed pregnancy or less than six months post-partum * Inflammatory disorders * Auto-immune conditions * Recent soft tissue injuries of the back in the last 3 months * Recent steroid injections to the back in the past 3 months * Recent spinal surgery in the past 12 months or scheduled/waiting for any major surgical procedures during the treatment or follow-up period or underwent rhizotomy or any neurosurgical procedures * History of neurological conditions, or psychiatric disorders (except depression and anxiety disorders) * History of cancer, or currently receiving/scheduled for receiving therapy for cancer * Cognitive impairments (dementia, Alzheimer's disease; indicated by a total score of 24 or below on Mini-Mental State Examination) * Alcohol or substance abuse * History of epilepsy or seizures * Presence of any electronic implants (e.g., pacemaker), metal implant in the body (particularly head and neck), or spinal cord stimulator.