Thanks for query,
You may go for MRI
of lumber region for clear diagnosis.
Due to straighteing of lumber Lordosis
The nerves going to thighs stretched leads to sciatica
.This is a reason of your pain since 13 years.
The loss of normal Lordosis cannot be corrected by operative methods this is a limitation of medical field.
However you may go for other measures like adjusting your posture accordingly by changing your sitting & sleeping position.
The other option is taking regular vitamins
like B1B6B!2 that will help your nerves as it works as nerve tonic.
You should start using hard surface to sleep & always take supine position.