For some reason I'm always questioning my supervisor.
What makes you want to question him all the time?
I'm wondering if I'm doing the right thing. I'm questioning his competence to lead the section
It seems like you might just need some reassurance that he can do the job. It is okay to question him as long as you do so in a respectable manner.
Because I'm considering a career switch to help with my insecurity.
Seems like you have a lot going on when it comes to the insecurities with your career and the management team. Having a one-on-one with your manager would be very beneficial so you could talk about these issues. After you gain that information you can decide what you would like to do for your future.