Severe pain in hips from prolonged sitting

Dear Doctor,

I am asking this question on behalf of my mother in law who has been experiencing severe pain in her hips muscles which is aggravated by prolonged sitting and relieved while standing or with the movement. Sometimes the pain is so much that she is not able to lie down as well. She has rheumatoid arthritis and has been experiencing this pain for almost ten years now. She has also got herself examined from various doctors but no one has been able to diagnose the real cause of the pain. In fact long time back she had done an ultra sound where it was revealed that her hip bone is bent slightly due to which when the muscle get trapped inside the bend the pain initiates.
However, she also says that the pain feels like there is a puss in her hips and the pain starts from the centre of the hip joint.
Doctor would be really grateful if you can suggest some remedy as she has been to various doctors with no successful result. One of the doctors have also suggested her Ayurvedic treatment .

Hoping to hear from you soon. Also please write me.