Hi Jan, I enjoyed understanding your thinking on this topic, and also how it got me exploring and thinking about my thoughts on feelings.
I completely agree that feeling and thinking get intertwined in the mind, and that it's beneficial to observe them and see them as separate things -- you understand and have more control over yourself.
You might be interested in the piece linked just below. It talks about how I see feelings and emotions through a rational lens -- coming at some of the same topics you do, but from the opposite side -- so it's kind of a response to your invitation:
https://medium.com/philosophytoday/the-will-to-reason-925c097411f1
As I understand it, many psychologists define emotions and feelings as two different things, although I agree they *feel* like the same thing.
Specific to where do feelings come from and why, the reading I've done on this point answers these questions from a biological perspective-- feelings have been hardwired into living creatures as survival mechanisms as a survival mechanism. As humans, we inherited this wiring, but with a deeper awareness of them, how they work, and how to manage them.
For instance, empathy is a survival mechanism -- an instinct -- to ensure you care about your family members. And worry is an instinct to keep you alert to dangers, etc.
The scientific explanations aren't a total answer, but I think I understand where feelings are coming from and why they work the way they do much more inb light of this background. With that as a leg up, I can focus on understanding the deeper mysteries.