Where do physical laws come from? Of course we can not know. We don’t even know if the physical laws are the same everywhere in the universe–we assume they are, but there is no way to be sure.
In the absence of knowledge, we have to give up, or guess. My current favorite guess is the landscape theory. In this theory, there are a vast number of universes, of which ours is just one. Each universe can have its own set of physical laws. Our universe is not special. The fact that we exist to observe it proves merely that the physical laws in our universe suffice to support our form of life (the weak anthropic principle).
This theory appeals to me because it satisfies the Principle of Mediocrity: we are not special. If we were special, we would have to understand how and why. Since we don’t understand, I think it makes more sense to assume that we aren’t special.