First we have to rule out whether the pain is because of a mechanical issue or it is inflammatory in nature. If pain is less in morning and improves with rest then it’s mechanical in nature. If pain is worse in morning hours and gradually improves with activity then it’s inflammatory in nature. Medical treatment of both is bit different. However analgesics is helpful. Start with walking as per tolerable limit and gradually increase to 3-4 km. Core strengthening exercises. Hot fomenting.

This treatment is being suggested on bases of the information provided. However I would like to examine & investigate the patient  in detail. -Control  Hypertension, Diabetes or  metabolic disorder, if there is any. -Any way it may be tried, --. Dolokind Plus (Mankind) [Aceclofenac100 mg +Paracetamol 350 mg] 1 tab. OD & SOS. X 5 days. --. Caldikind plus  (Mankind) 1 tab OD x 10 days. -(You may need help of your local doctor to get these medicines.) --. Fomentation with warm water. Let the part not be exposed to cold. --. Sleep on a hard bed with soft bedding. --. Use no pillow under the head. --. Avoid painful acts & activities. -- .Do mild exercises for the affected part.- --.(Take help of physiotherapist or you can visit my YouTube channel Dr. N. C. Gupta and watch 'Me & My Yoga' and 'Yoga Simplified'. https://youtube.com/channel/UCPEQc6B1ywzwin048JSu6rw --Do not ignore, let it not become beginning of a major problem. --Do ask for a detailed treatment plan. Kindly make sure, there is no allergy to any of these medicines. --For emergency treatment visit nearest hospital. --Wish you a quick recovery & good health. --I hope, I have solved your problem to your satisfaction.  Dr N C Gupta MS (ortho)

Back pain can be due to various conditions. If she has been seen by various doctors and not helped then have to consider missed diagnosis. Can consult here for prescription. Ask her to do back strengthening exercises and keep proper posture.