Question

why is it that nobody is in absolute rest or in absolute motion

Answer 1

actually it cant be specified that a particular body is in rest or motion until its inertial frame is decided....

Answer 2

We know no particles can go more than speed of light.

They are not in absolute motion. If anything more than speed of light then it can say in absolute motion. Just nearly scientists found an element which is more speed than light like tyckon. So absolute motion can be possible.

Now. suppose you kept a body or wooden log on the ground with no movement.
And now u will say that it is in rest.
But just think , the gravity is acting on that body but normal force oppose it.

If it is difficult to understand, then think whatever we see is in rest. But still it is in motion as our Earth is under motion. Our solar system is in motion, Galaxy is in motion and also the universe in motion so indirectly the wooden block is in motion.
So absolute rest cannot possible.