Study about how position of head influences thoughts
Hue,

It sounds like you are interested in a field of research known as embodied cognitive science. It is a fascinating field that looks at how we use our bodies and environments in conjunction with or instead of our brains to complete some cognitive task.

I suggest you start by reading Risko &amp; Gilbert (2016) for a recent review of a phenomenon known as "cognitive offloading" which I think will give you some interesting insights to some of the questions you posed. Evan Risko has done some interesting work on the effects of head tilts on cognition which I think you'll find interesting.  If you can't access the article due to the paywall, let me know, and I can send it to you.

Unfortunately, I do not know any research on dreams and such.