Hello, I have studied your case with diligence. As per your history there is possibility of monoarticular arthritis. Rheumatoid arthritis may involve small joints and early morning stiffness in joints, does she have such complain? Ankylosing spondylitis typically involve spine and hips with other large joint also. There is reduced chest function in this disease. Stiffness in spine is increased does she have such stiffness in spine? Harmone imbalance like hypothyroidism also leads to similar complain.so check your thyroid profile. Hope this answers your query. If you have additional questions or follow up queries then please do not hesitate in writing to us. I will be happy to answer your queries. Wishing you good health. Take care