For each of the following cases, select the single most likely diagnosis from the options listed. Each option may be used once, more than once, or not at all.
A A 38-year-old painter and decorator presents with gradual onset of pain in both shoulders, left worse than right. This is especially severe when he is trying to paint ceilings. On examination, pain is experienced at between 60 and 100 degrees of abduction. Shoulder radiographs are normal.