Yes.
Running is not walking .
The feet, ankle, knees and hips go through a different range of movement. This is only possible because your going faster than walking.
Example;
You walk from heel to toe, catch your self and repeat. Your legs are straight and only slightly bent on the back stroke.
If you ran like that you would be driving your legs straight into the ground. Effectively stopping and starting, rather than having a smooth gait.
You run knees bent, slightly lean forward, strike mid-foot catch yourself repeat. Legs are very bent on the back stroke.
Now the slower you go the harder it is to do this circular motion as the stride length inhibits the smooth flow and it becomes more efficient to walk. That is why very slow runners look so "crouched" in on themselves rather than "open" and more errect than faster runners.
"Shoulders back, chest out" opens up the stride the chest the lungs.
To find your easy pace I would, if you have at least one race time, use a pace calculator. They are easy to find on the internet and try a few to get a good average and a range you can run from the fastest to the slowest. If you have no race times set time aside to run say 5k as fast as you can and use that.
Good fortune