The International Headache Society classifies cervicogenic headache as a secondary headache caused by a disorder of the cervical spine and its components. Mulligan Concept (SNAG) is a gentle manual therapy that can be applied to the neck area. The myofascial release technique is also a massage-type manual therapy technique that is widely used in physiotherapy to relieve pain and tension in the relevant muscle group. This clinical trial aims to investigate the effectiveness of the Mulligan Concept and myofascial release technique in patients with cervicogenic headaches. The main questions it aims to answer are: 1. Does the Mulligan Concept improve hand grip strength, pressure pain threshold, range of motion, pain frequency, pain intensity, pain duration, number of medications used, daily living activities, and disability in patients with cervicogenic headache? 2. Does myofascial release technique improve hand grip strength, pressure pain threshold, range of motion, pain frequency, pain intensity, pain duration, number of medications used, daily living activities, and disability in patients with cervicogenic headache? Researchers will compare the Mulligan Concept to a myofascial release technique to see which physiotherapy method has more significant results in treating cervicogenic headaches. Participants will: * Undergo the evaluations mentioned above before and after interventions * Undergo Mulligan Concept applications or the myofascial release technique 3 times a week for 4 weeks * Keep a diary of their symptoms and the number of times they use a drug