What causes vaginal walls numbness?

What causes vaginal numbness in your vaginal walls? I don't even feel the sensation during sex. is this part of having a csection a year ago? I also have vaginal dryness if that causes vaginal numbness. I have had a vaginal exam twice and my doctor hasn't said anything wrong down there. I don't even have a sensation when my stomach is hungry or when I have to pee. I have to guess when to eat and pee. I had my son on July 14th 2016. I just hope this is normal!!!☹