Welcome to healthcare magic!
After going through your case history. I would suggest few more test for your mother
1. Vitamin D3
2. PPBS and FBS
Because the most common reason for such pain is disc prolapse
which has been already ruled out in your case as mri and CT scan are negative. So now it can be some neuropathic pain
which can arise due to either diabetes or hypertension
or due to Vitamin D3 deficiency. And if I would have been your treating physician then i would have started some neurogenic pain revealing medicine like Neurobion
Forte along with the other medicines., If you have any questions further then I am right here . Take Care.
Wish you a speedy recovery
Dr. Medhavi Agarwal ,
General & Family Physician