Burning sensation may be due to local inflammation or irritation of nerve roots.
Since the problem is chronically present, you should get her evaluated to rule out any neurological cause.
Next Steps
She may start Vit
B12 and Pregabalin medicines.. Clinical evaluation will be more helpful for better diagnosis.. She may start Ankle and foot exercises.. She may require Nerve conduction Study of the involved Lower limbs..
Health Tips
Apply cold crea ointment over feet before sleeping. Use socks.. Hot fomentation may also help..