To further understand what is going on do a "Google" search for radiculopathy and nerve dermatomes. Dermatomes are pathways that are unqie to each nerve branch and define the point at which the nerve leaves the vertabra. The combination of pain you describes is fairly definitive for compression of a nerve at a specific cercical level. The vertebra are divided into cervical, thoracic and lumbar sections, with a letter and number assigned each segment. Generally there is inflammation involved and a combination of a mild anti-inflammatory such as motrin (Ibuprufin) should be combined with range of motion exercises. Rotation of the head around and around 360 degrees puching it to it's limit of flexure down at all points is often helpful, but sometimes impossible information to convey to a stroke patient. You can help them by doing this yourself in front of them. The exercise should be repeated three times a day for a couple of weeks. We are assuming, of course that there is no "broken neck" or tumor which is causing the pain. Positionally relieved arm and shoulder pain is almost always due to compression of a nerve at the cervical level.
Yes. A physiotherapist is the answer. The manipulations suggest a pinched nerve, which can be in various places and the physiotherapist will know exactly what manipulation. Often, but not always, the pinch is in the cervical vertebrae.
My husband suffered from shoulder & arm pain after a stroke until a physiotherapist (Dr. Vasa) taught me how to do certain fairly simple manipulations of his shoulder and scapula, which relieved the pain after about a week of doing the manipulations. She tells me that what she taught me is absolutely routine and is known to every PT & OT. If that's true, I don't know why no one showed it to me in the months my husband was in residential rehab. Anyway, ask around among PT's & OT's until you find one who will show you how to do this. Wish I could just tell you how to do it, but there's no way I can explain it in words. You have to be shown.
First ascertain that the pain is due to a stroke and not nerve compression at the cervical level. You can do this simply by applying gentle axial traction to her head while she is experiencing the pain. If it is due to cervical compression than axial traction several times a day and an antiinflammatory are indicated. Subluxion injuries are common in stroke survivors secondary to neck flexure after a fall. If an arm sling provides help, it probably is nerve compression. There are several tests, such as an EMG, that can determine the exact nerves involved. A cervical collar may work, but will cause loss of muscle tone, so is contraindicated. If the axial traction relieves the pain (it will either do so almost instantly or not) see an M.D. who specializes in subluxion injuries.