Chronic neck pain (CNP) is the commonest musculoskeletal condition. In any pain, Autonomous Nervous System (ANS) is modulated with the upgradation of sympathetic component leading to increase in allostatic load, resulting in increased vital parameters which further may result in Dysfunctional breathing (DB). Heart rate variability (HRV) is a biomarker which reflects the function of the ANS significantly. Assessment of the HRV is non-invasive technique and can be an approach to assess ANS. As the pain is related to ANS dysfunction, leading to DB, CNP was treated with Transcutaneous Electrical Nerve Stimulation (TENS) along with Jacobson's Progressive Relaxation Technique where TENS reduces pain by regulating pain gate mechanism and Jacobson's Progressive Relaxation Technique normalizes the upgraded sympathetic component of ANS, resulting in balanced ANS. As a result of this, DB and altered HRV is normalized.