I have an older cat that seems to get harassed by my kitten,
The kitten always chases and bites my older cat behind the neck.
My older cat would yelp and runs away and the kitten proceeds to chase my older cat down.
I would think that if my younger kitten is playing too rough the older cat would show him whos boss right?

If the other cat is yelping that most likely means the kitten is causing it pain and should be put in check before causing harm to the older cat

depends how muchn yelping happens per day

if it's once in blue moon type of thing,they prob were playing and just got too rough

if it happens once every day, separate them for a bit

No kitty

Youd think older cat would smack the shit out of him, but maybe kitten is becomnig dominant alpha. Let em be, theyll sort it out.