Suggest Treatment For Pain And Stiffness In Thighs

My mother has had a pain and stiffness in her tighs for more than a month. She visited a doctor and the doctor prescribed injections for 7 days. On the fourth day after she had the injection she had pain and her thighs was very painful and still and could hardly walk. then she went back to her doctor again and her Doctor prescribed to do physio therapy for 10 days and it didn t work at all. The stiff ness and the pain is still there and we do not know what is happening, and what to do next. Can you please assist? I am more than happy to give more information if needed? Thanks,