'외치고, 또 외쳐도
다시 돌아오는 메아리처럼
이런 내모습이 익숙해질까봐
너무 두려워'
To help with understanding, it can be rearranged like this.
외치고 또 외쳐도 다시 돌아오는 메아리처럼, 이런 내 모습이 익숙해질까 봐 너무 두려워.
It may be translated:
(literally) Like an echo that comes back every time even if I shout again and again, I am so afraid I might get used to the way I am now.
(with simplification)
Like an echo that returns every shout I make, I am so afraid of getting stuck with how I am now.