1. Need a proper X-ray pic ,try to post the lateral view of the LS spine X-ray as a proper image
2. lower back ache can be due to slip disc or facet arthropathy at elderly
3. For generalised weakness get a electrolyte and Vit D level and her haemoglobin levels checked
Next Steps
Proper X-ray pics additional lateral LS spine X-ray too and above blood tests
Health Tips
Avoid to bend down , lifting heavy weight, sitting upright , spine strengthening exercises . A mild analgesic with muscle relaxant will do for short term