Find out why. Never assume that a stroke patient doesn't know what they talking about. If they say there is pain, assume there is and then get a description. Then investigate what is going on. If you can't do it (because pain problems in otherwise normal people are often difficult to resolve), take the patient to a doctor who often deals with stroke patients.
F/u with Neurologist. Take him to the neurologist who may try medicines for neuropathic pain like lyrica, (pregabalin) Gabapentin or others. Otherwise take him to pain management to help him control the pain. Attempt to pinpoint where is the pain located, which joints, or between joints, the back, the neck, shoulders, knees, elbows, hands? May benefit fron cortisone shots.