I am experiencing constant pain in my lower back a bit above the scarr where i had surgery for spina bifida. what could be the reason for this?

Painful Back Scar: Scarring from any surgical procedure can cause pain in both the short and long-term. In your case, I would be more concerned because spina bifida is a complex issue requiring long-term follow-up to monitor neurological function and any changes in spine pain and stability. If you haven't see a spine surgeon in a while, my recommendation is to get an evaluation with x-rays and possibly an MRI.