Telerehabilitation, Face-to-Face Exercises, and a Mixed Model in Chronic Non-Specific Neck Pain

The goal of this clinical trial is to compare the effectiveness of different physical therapy delivery models in treating chronic non-specific neck pain in adults aged 20-40 years with a history of neck pain for three months or longer. The main questions it aims to answer are: * Which approach (tele-rehabilitation, face-to-face exercises, or a mixed model) is most effective at reducing neck pain intensity and functional disability? * Are there significant differences between the three models in improving cervical range of motion, kinesiophobia (fear of movement), patient satisfaction, and adherence to the exercise program? Researchers will compare three groups to see if the delivery model affects outcomes: 1. A tele-rehabilitation group receiving real-time, video-guided exercise sessions. 2. A face-to-face group receiving traditional, in-person supervised exercise sessions. 3. A mixed-model group receiving a combination of both tele-rehabilitation and face-to-face sessions. Participants will: * Be randomly assigned to one of the three groups. * Engage in a structured exercise program for 45-60 minutes per session, three times a week for six weeks. * Follow a phased exercise protocol that begins with mobility and pain reduction, progresses to strengthening, and finishes with endurance and functional training. * Complete assessments for pain, disability, range of motion, and other outcomes at the beginning and end of the 6-week intervention, with a final follow-up at 3 months.