I had a lucid dream last night, and I knew I was dreaming and everything, but no matter how hard I tried, nothing would change, I tried to make the ground change color, I tried to change the scenery, but nothing would change, everything just went on its normal dream path
It's probably a subconscious barrier that is preventing you from changing things, like a niggling doubt in the back of your mind. Next time, take a step back and tell yourself "I am dreaming. This is my dream and it is possible for me to change things." Really mean it too! If you can convince yourself, the rest will follow easily.