A 65 year old man with multiple vascular risk factors was admitted after a stroke. Five days later, he complained of left shoulder pain. This was a dull ache, worse on movement and on touching the shoulder. He also voluntarily described a second different pain, as a “clawing at the flesh” that was constant. Abnormalities on examination were a global decrease in the range of left shoulder movement, dysarthria, left pyramidal weakness, left hemisensory diminished pinprick sensation and decreased sensation to touch and temperature in the left upper limb. “Referred” allodynic pain was experienced in the shoulder joint, when the skin over the left scapula was touched. A left shoulder radiograph was normal. Central post stroke pain (CPSP) was diagnosed and amitriptyline 25 mg nightly was …