Hello, I have studied your case and reports with diligence. At age of 75 there can be degenerative wear of bones, muscles, ligament and facet joint arthritis, due to deficiency of calcium, vitamin D, VIT B12.so supplements of these nutrients can relieve pain. Osteoporosis may be associated leading to diffuse pain in back. Check your bone strength with DEXA SCAN and you can start medication according to level of osteoporosis, And also check your vit B12 and vit D3 level. You can reduce pain by doing regular exercises and medication. I will advise you to do regular physiotherapy and exercises as my patients find much relief by these therapies. You may consult physiotherapist for guidance. He may start TENS, or ultrasound which is helpful in your case you need to take diet rich in calcium and vitamin D. Along with the pain you have depressive symptoms as well and that needs to be taken care of. Cognitive behavioural therapy is a good option. Many of my patients get relief from fatigue by yoga pranayama and sudarshan kriya so you can also due that. 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. If you find this answer helpful do not hesitate to rate this answer at end of discussion. Wishing you good health. Take care.