Restless legs syndrome (RLS) is a common neurological disorder with an irresistible urge to move the legs and discomfort that worsens at rest or in the evening and is relieved by movement. Variant RLS occurs when symptoms spread to the arms, abdomen, or bladder but still meet the International RLS Study Group diagnostic criteria. The article describes the case of an adult female patient with refractory right shoulder pain, initially diagnosed as frozen shoulder. The correct diagnosis of the RLS variant was confirmed by polysomnography, which showed an increased index of periodic limb movement during sleep and a supportive score of the International RLS Rating Scale. Treatment included iron supplements for iron deficiency anemia and pramipexole, after which the shoulder pain and other symptoms improved significantly. This case illustrates the RLS phenotype with pain predominance in the upper extremity. The authors provide a summary analysis of previously reported cases of restless shoulder syndrome and emphasize the need to include the RLS variant in the differential diagnosis of unexplained shoulder discomfort.