Hair always falling out if i dont straighten it?

I think that you hair is just a little bit unhealthy. The best thing for you to do would be to trim your dead ends. I know you want your hair to grow longer, but more than half of the time a healthy trim will cause your hair to grow longer, faster. Maybe your hair is just used to the pressure of the straightening iron, and when your hair is straightened it causes it to stay in place.