HI, thanks for using healthcare magic
Burning pain is most commonly due to neuropathy which is abnormal function of the nerves.
This can be temporary or permanent and there are different possible causes.
Some of the more common causes are:(1)trauma to the nerves- this is the likely cause for you with a history of lower
back pain and surgery to the back. The nerves from the back supply the thigh and legs and if they are affected by the surrounding bones , this can cause neuropathy
(2)diabetes
(3)side effect of medication
(4)low levels of
vitamin b12 or folate
(5)abnormal levels of vitamin b6
(6)
thyroid disease
(7)liver or
kidney disease
(8)infection such as shingles
(9)exposure to toxins
(10)
stroke, ms
(11)some types of cancers- rare cause
Though the issues with your back are the likely cause, you may want to see your doctor to rule other potential causes.
This would require physical examination and blood tests.
There are medications that can help with this type of pain/sensation
I hope this helps