Hello, Welcome to healthcare magic. I am so sorry to know that your mother is suffering from such a problem. pain at the night associated with swelling,aggravated during inactive period & subsided during movement are the features of inflammatory arthritis. These arthritis are particularly common in female person. Some investigations are needed to exclude the cause( cbc,esr,ra,anti-ccp). proper physical examination is also needed. It is better for you to consult a doctor. take care.