I am a layman and this is my first ever question! Although, it is simplistic in nature, I hope that there is a beauty in its simplicity which could give a simple answer.
Alan Watts, the philosopher, stated 'Why is there any Energy at all? When, nothing or nothingness is so much easier'. Why then does the Universe 'go to work' and have energy, why and for what purpose?
Why is there any Energy at all?
The simple answer that is preferred by modern physicists is that there is energy because the laws of physics are the same today as they were yesterday. It is the fact that the laws of physics do not change over time that leads to energy.
Of course, that begs the question "why are the laws of physics the same over time"? That just seems to be how the universe works.
Physics does not in general answer the question of why something fundamental exists, nor does it seek to assign a purpose to anything. Rather, it tries to build a model to understand how different fundamental things interact with each other. Energy is one example. It is not a theoretical artifact, but rather a physical substance intrinsic to the Universe. Physicists are concerned more with the mystery of how energy interacts with matter, how it transforms from one kind to the other, etc. -- and not so much why it exists at all.
The latter happens to be a rather pointless line of inquiry, best left to the likes of philosophers to squabble over :)
