Chronic musculoskeletal pain (CMP) is a common disease in China, with a high incidence among the elderly, and has a significant impact on patients' quality of life. Shoulder osteoarthritis is a common type of CMP. Currently, both domestic and international studies have confirmed that glucocorticoid injection at myofascial trigger points(MTrPs) can alleviate patients' pain symptoms. MTrPs injection is safe and easy to operate, and can improve the clinical management efficiency of patients with shoulder osteoarthritis. Therefore, we designed a prospective, randomized controlled, blinded outcome, non-inferiority study to compare the long-term clinical efficacy of glucocorticoid injection at myofascial trigger points and complex intra-articular injection in treating shoulder osteoarthritis. Patients will be randomly divided into two groups and receive either glucocorticoid injection at MTrPs or joint cavities. After treatment, patients will be followed up for 2 years. Their NRS scores, WOMAC scores, Patient Global Impression of Change(PGIC) scale, and adverse reactions will be recorded at 2 weeks, 4 weeks, 8 weeks, 12 weeks, and 24 weeks. If the results indicate that the clinical efficacy of myofascial trigger point injection for shoulder osteoarthritis is not inferior to that of injection at intra-articular injection, it will provide a safe and simple treatment option that is easy to promote for patients who do not respond to conservative treatment.