68-year-old man, right hemiplegia after stroke, right shoulder ache

A 68-year-old right-handed man, 3 weeks post-left MCA infarct with dense right hemiplegia, presents to acute inpatient rehabilitation with a 7/10 aching pain in his right lateral shoulder, worse upright and during transfers. Two days ago, after a nursing aide pulled on his right wrist, he developed new burning pain radiating down his lateral right arm, and his previously developing biceps tone disappeared.