As individuals, we are micro-cosmoses living in a universe of possibilities. Unless we die, which is the only things we are ever compelled to accept as inevitable, we hold the freedom of choice, the free will. Whether it's influenced by external or internal stimuli, whether we find ourselves confused at times, whether we feel there's not enough data in order to take an informed decision, the ultimate act of deciding and acting upon it is ours - free-will is real.
Within us, we carry years of education/conditioning, upon which we've created patterns of functioning as individuals. Apart from this, we've accumulated our own experiences and filtered them through our consciousness in order to constantly adapt to our coping with the environment.
In short, a human being is a unique construct, but that's already been known for quite a while. We all live in separate universes, colliding into each other
within reasonable, antagonist or even ridiculous or absurd reasons.
Although we communicate with others in so many ways, we are alone. We can relate to what we perceive from external sources such as other individuals, but we cannot re-live their experience, we can not replicate their exact lives. What we call understanding is merely a convenient phrasing of the fact that "I am trying to match that to a former experience of mine or imagine the thing".
Hence, the solitude we dwell in, more or less unconsciously, is actually the freedom we were born into, yet we've forgotten about it somehow. We are born alone into this world, we live alone and we die alone. What we make out of relating to the surrounding environment or other individuals should only be a way of learning to exercise our freedom, and free-will helps us achieve that.