Background: Shoulder pain is a common problem imposing a considerable burden on the affected person and society. Since interventions targeting traditional musculoskeletal conditions are usually only moderately effective, myofascial origin can be suggested as an alternative possible source of shoulder pain. Objectives: To examine current evidence associated with myofascial origin of shoulder pain, with emphasis on diagnosis, prevalence and treatment efficacy. Methods: PubMed, Google Scholar and PEDro databases were searched from inception until December 2013 for terms relating to myofascial pain in the shoulder area. Results: Two studies showed a high reliability of the following diagnostic characteristics during palpation: presence or absence of the taut band, spot tenderness, jump sign, pain recognition and referred pain sensation. Three prevalence studies showed a significant greater number of active myofascial trigger points (MTrPs) on the painful shoulder side. Reduced muscle strength, accelerated muscle fatigue, inconsistent muscle activation pattern under load and reduced antagonist reciprocal inhibition were found in subjects with latent MTrPs in four observational studies. Six interventional studies demonstrated the effectiveness of dry needling, myofascial manipulation, ischemic compression, laser therapy and multimodal treatment. Conclusion: MTrPs in shoulder muscles is a common condition among patients with shoulder complaints and can be reliably diagnosed by palpation. The reviewed interventions seem to be effective in reducing pain, increasing range of motion and improving function of the painful shoulder.