The song is 僕は頑張るよっ by 神聖かまってちゃん。
The lines that I find confusing are "あーでもないこーでもない 人間はめんどくさい" and "パーでもないグーでもない 悩んでばかりいます". Specifically, the first parts of each line.
In the translations of this song, that I found, different people translate these parts differently. Some translate "あーでもないこーでもない" as "It’s neither this way nor that way". And others translate it as "Humans who are neither uh nor uh are annoying". In regard to the second line "パーでもないグーでもない", I've seen people translating it as "It’s neither bad, nor good" or just giving up and just writing "I’m not a par or a goo". I personally think it might be some rock-paper-scissors related analogy, as パー seems to represent paper while "グー" represents "rock".
(Edit: perhaps I should clarify, that the confusing parts are "パー ", "グー", "あー" and "こー")
I hope someone can explain or suggest what those lines mean and if any of the translations that I found are correct.