Murder is not a right, natural, given by God, or anyone else. Self defense, on the other hand, is a right that exists exclusive or any document. The US Constitution limits the actions of government and specifically enumerates rights that were considered most important. Additionally, it does not limit those existing rights to those enumerated.
The framers of the Constitution intended to create a document to confirm those rights and limit government’s ability to interfere with them. It has worked reasonably well over the centuries, proving to be well written and durable.
Your argument is with the framers if you believe that you have the right to murder. I’m pretty sure they did not intend that or believe it.
God gave humans free choice. That means as a human being you are free to choose to murder someone. Nowhere in the Bible does it say that we should murder people and nowhere in our constitution does it protect that right. And that is a good thing. It also doesn’t protect the right to Rob or steal or rape or any of those other things. Those are all things that God has given each individual the right to choose to do or not do. And that choice will have ramifications.