You think you have a will, but that is a misconception about your ego. The will as a tangible thing does not exist. You want something at a certain moment after you choose from different wishes. And that choice can change within a short time, perhaps even to the complete opposite.
Is a thought simply the sum total of the activity of all the neurons in the brain? No, just as a message is not simply the placement of a sequence of letters which follow the rules of grammar. How do those letters stand in relation to that message? How does the activity of neurons stand in relation to a thought? Was Descartes right, or are we our brain?