Hey you are actually really good!
For a smooth run you need to keep your back at the same position(angle), control your back using your legs. It's kinda hard for me to explain but I think you're smart enough to figure it out =D That's the fun part of running.
To make equal sized steps, your pecs and hips have to be balanced at all times. But this is close to impossible because for example when you extend and contract pecs, your chest which is on hold, starts to rotate by itself due to pecs. And also glutes tend to adjust by itself.
You already have a firm idea in running so all you need to do is practice x1000
I have an example replay for you: