No, I do not "own myself." It is not possible for myself or any other person or entity to "own" me, because I am not a piece of property.

I think we disagree. For clarity the claim I'd make is: You own your body. In that sentence the 'You' refers to what I loosely call the animating intelligence, that's whatever component or system, in a human, that exhibits intentionality - that's the thing that can be a property owner. The brain has a much closer relationship to 'You' than does your little finger. Though both are parts of your body, and are (I claim) owned by 'You'.

'Your body' includes the physical substrate that 'You' (the animating intelligence) emerges from.

And 'Own' means that you have the exclusive right to determine how the physical stuff that makes up your body may be used. For instance, you (and you alone) have the right to decide who else - if anyone - gets to use your spleen, and how.