Newly diagnosed and confused about the goal

I am newly diagnosed PMR by my primary doctor. My symptoms started slowly with stiffness and pain in my hamstring area of my left leg only. Over a 3 month period of time the stiffness, pain, and feeling like the muscle would just snap in 2 spread to both legs and lower buttocks area, then to both hip girdle area. My doctor thought I might have sciatica and sent me to PT and an X-ray. X-ray showed L5. l4 area usual arthritic changes in a 73 year old body. PT made me feel better overall physically, but did nothing for the pain. Doctor then did blood work which showed protein reactive score of 17. Put me on 15 mg of prednisone. I have only been on it for 9 days. Some ever so slight improvement in morning pain, it doesn’t last quite as long as before medication, but still uncomfortable. If the leg pain is better the hip pain seems worse.
Is the goal of the prednisone to eliminate the pain or just lessen it? How long should I wait before saying although better the pain isn’t all that much better. I am not sure how to measure this. I am happy for any level of pain relief but was hoping for something better than what I am currently experiencing. I am expecting too much too soon?