Arm, Hands, Shoulder Pain & back pain.

Hi all, a sincere request to answer my question as me and my mother are both left bemused as to what's wrong with her. My mother is 66, undergone heart surgery last July and her weight has dropped to 48kgs. In the last one year she has recovered from migraine based vertigo and frozen shoulder from which she recovered in Jan. But snce last few weeks her shoulder and her arms start aching intensly only when she sleeps and her recent x ray has also show spondylitis slightly. We are left with no option but to take her to a doctor for the 100th time in one year. This process is very depressing , financially burdening and risky for us due to covid situatio. Can the orthopaedic fraternity please try to answer what is the reason for this intense pain mostly in her arms and hands which occurs only when she sleeps. She is an old lady who is in pain when she goes go sleep and even she wakes up she has experience it for half an hour pls request you humbly to describe the root cause of this issue.