Hi and welcome to HCM
Your mother might be suffering from peripheral edema
To get relief from the pain:
Elevate your legs above your heart while lying down.
Exercise your legs. This helps pump fluid from your legs back to your heart.
Wear support stockings.
Follow a low-salt diet, which may reduce fluid retention and swelling.
Avoid sitting or standing without moving for prolonged periods
of time. Exercise regularly. Lose weight if she need to.
I do hope that you have found something helpful and informative and I will be glad to answer any further query.