The Effect of Vagus Nerve Stimulation on Pain and Functional Activities in Individuals With Chronic Widespread Pain

The goal of this clinical trial is to examine the effect of vagus nerve stimulation (VNS) on chronic, widespread pain in adults. The study will also evaluate which method of VNS-electrical ear stimulation or deep exhalation breathing-has a more significant impact on pain intensity, quality of life, and emotional well-being. The main questions it aims to answer are: Does vagus nerve stimulation reduce pain intensity in individuals with chronic, widespread pain? Which intervention-electrical ear stimulation or deep exhalation breathing-provides a greater improvement in autonomic function, emotional status, and quality of life? Researchers will compare two active interventions-electrical ear stimulation and deep exhalation breathing-to a no-treatment control group to determine relative effectiveness on pain and related outcomes. Participants will: Be randomly assigned to one of three groups: * Electrical Ear Stimulation: Apply a small, non-invasive device to the ear for 20 minutes, twice daily for two weeks. * Deep Exhalation Breathing: Perform balloon-blowing exercises (four deep exhalations per set) once every waking hour each day for two weeks. * Control Group: Receive no intervention during the two-week period. These participants will complete baseline testing, return after two weeks for follow-up testing, and then be debriefed. They will have the option to withdraw or receive an active treatment after study data collection concludes. Complete four questionnaires to assess pain, emotional state, and quality of life. Undergo physiological assessments including heart rate variability, neck muscle tissue flexibility (via MyotonPro), and pressure pain sensitivity (via pressure algometer), both before and after the 2-week period. Participation includes two in-person sessions (approximately 1 hour each) and daily home practice (for intervention groups) lasting 40-60 minutes per day for two weeks. The study involves minimal risk, and no compensation is provided.