[Purpose] The study aims to examines the effects of proprioceptive neuromuscular facilitation (PNF), extracorporeal shockwave therapy (ESWT), and trigger point injection (TPI) on pain reduction and functional improvement in patients with Myofascial pain syndrome (MPS) of the upper trapezius muscle and compares their treatment effects, thereby presenting precise and efficient treatment methods. [Subjects] Thirty-three patients with MPS in the upper trapezius muscle were divided into three groups: a PNF group (n=11), ESWT group (n=11), and a TPI group (n=11). [Methods] The degree of pain was measured using the visual analog scale (VAS). Pressure pain threshold (PPT) was measured at trigger points in the upper trapezius muscle by using a pressure algometer, and the Constant-Murley scale (CMS) and neck disability index (NDI) was applied for functional evaluation. [Results] A comparison of the effects of the different treatment methods revealed no significant differences among the groups in terms of PPT, but CMS (pain, range, and activities of daily living) and NDI showed significant differences among groups. [Conclusion] PNF treatment enhanced neck function, range of motion in the shoulder joint, and activities of daily living relative to the other methods; ESWT reduced degree of pain and improved functioning. TPI treatment reduced pain, but had limited effects in enhancing functional activities.