It's in your mind which I guess is a spiritual part.

Its between my ears.. my inherited (genetic) make-up environmental influences during my lifetime, how well I look after myself, stuff like that.

It's all of my, my heart, my mind, my body, my experiences in life, what I learn and how I change throughout a lifetime.

It's a construct - there is no Self ^_^

This is a word with many meanings, most of them are useful in some specific context. But there's one context in particular where this word causes a ton of trouble, and that's when we start talking about who we are in an ultimate sense... i.e. the eternal "quest for personal identity". In that quest, the answer is a moving target: it keeps getting bigger all the time. That's what screws people up, because "myself" is not a fixed thing, but a continually expanding field or container -- it's the context or space in which life occurs for me... the thing that holds all the other things. That's about as close as I can come to explaining it, but the explanation is less than helpful. What matters more than the explanation is an accompanying discipline which attends this understanding of 'self' -- it's the discipline of learning to continually let go of old versions of self so that you can expand to fill the new space that is being continually created. This is hard to do, because we are pretty much wired up to cling to our ideas of self, and that clinging prevents the transformation needed to keep "becoming self" ongoingly. So for most people, the way this works is that they cling to their idea of self as long as they can, until the pain is just too severe, then they have a sort of "identity breakdown" in which they question who they are, and that frees them up enough to expand so that they can be at peace again. Then they get an idea of the new self, start clinging to that, and the cycle starts again. This is the hard way to self-actualize. It's much easier once you get the pattern and start working proactively to avoid clinging in the first place.

Its in the mind, I can agree to that. The pleasure center is there, too.