I think I know exactly what your problem is, and the good news is there is sort of a fix. I had this exact same problem in the early missions -- I kept running into things because the camera would switch to the rear view. What I eventually figured out is that my controller's L3 button is very sensitive, and when I would push hard in one direction, it would often trigger L3, which is the look-behind button. Once I realized the problem, I was able to be more careful about hitting it. It still happens sometimes when I get carried away, but the key is to be gentle on the analog stick. Hope that solves it for you.
