To evaluate the effect of ultrasound-guided PRF stimulation and hydro-section by normal saline injection compared to local anesthetic effects on myofascial trapezius muscle syndrome. A randomized clinical trial study that conducted at pain clinics in Baghdad / Iraq for a period from Jun. 2020 to Dec. 2021. It included 40 adult patients diagnosed with myofascial pain syndrome of trapezius muscle for more than two months of pain and no signs of inflammation or cervical disc herniation and randomly allocated to one of two groups: Group A included 20 patients underwent ultrasound-guided PRF and hydrodissection with normal saline plus 40 mg of lidocaine and group B included 20 patients received a mixture of normal saline plus 40 mg of lidocaine by ultrasound. Follow up and evaluation were done for patients by using numerical rating scale for pain before procedure and after two, four, and eight weeks of treatment. No significant differences in age, gender, body mass index, pretreatment pain and duration of pain between study groups. Pain was significantly decreased two, four, and eight weeks after treatment in both groups compared to that before treatment. It was significantly lower in group A four and eight weeks after treatment than that in group B. No difference between PRF and injection of lidocaine in short term relieving of pain but PRF was preferred as a long term relieving of pain in addition to the safety and cost-effective property, noninvasiveness, and easy to be performed so that it can be useful in repeated outpatient clinics.