I've already gone through and corrected the kanji and romaji (and typos in the footnotes)
This is a translation correction so please could you handle this @bluepenguin

I'll proceed in the order kanji, current translation, recommended translation, justification (just in case).

Both reason to live here
Both the reason I'm alive here
[it would make more sense for it to be 住む if it meant live in that sense]

The pain pierces my chest
Everytime time happy people (bystanders) laugh (sneer)
Pointing at my size'
A prickling pain pierces my chest
I turn my back to those who are so happy (bystanders)
Who laugh (sneer) at that pain

[Looks like OP mistook チクリ for チンチクリン and also ignored the それ and the third line (which admittedly was originally romanised wrong)]

My trembling legs start to remember... surely
I can't protect my dreams (illusions)
With this unreliable power
Now, knowing this hand, I won't lose my way
My legs, which begin to tremble, remember this... which becomes my certainty
With just dreams (illusions) I can't protect
It's an unreliable power-
Now, my hands have felt it, so I won't lose my way

If a hundred, a thousand inevitable accidents happen
And I concentrate my eyes on watching the end... I'll go past them
I don't need countless careless wishes,
The number of coincidences outweigh a hundred or thousand certainties
I focus my eyes looking at the end... and jump over it
I don't need countless lazy wishes