A 71-year-old lady was referred by her general practitioner to an orthopaedic clinic for management of shoulder pain. The patient complained of pain in the shoulder and chest region but also described reduced sensation and power in her arm and a worsening of her respiratory symptoms. These prompted further investigation with an isotope bone scan which showed a large soft tissue mass posteriorly in the apex of the right lung with chest wall extension and destruction of adjacent ribs. A subsequent CT scan identified Pancoast's tumour. This case highlights the importance of considering non-musculoskeletal causes of shoulder region pain.