Some questions about the lyric of "so feel autumn rain"

Question

so feel autumn rain

Can 'feel' be modified by 'so' without saying what's the feeling?

Leaving with twilight though I was chosen

Why 'I was chosen' can be the cause of 'leaving with twilight'. You didn't chose, You were chosen. (and be chosen for what?)

I find the dreams are to stay

Who to stay? the dreams or 'i' ? I just don't know which is the object of 'find'.

Full lyric:

Leaving with twilight though I was chosen
To wander the way in the darkest of nights
Oh, in the summer sun how soon I came to stray
A true damnation, when I turned away

So fell autumn rain, washed away all my pain
I feel brighter somehow, lighter somehow to breathe once again
So fell autumn rain, washed my sorrows away
With the sunset behind somehow I find the dreams are to stay
So fell autumn rain

Blinded by dawning so you would take me
Further away, away from the fall
Oh, you told me I must never dream again
A true damnation, you left me the pain

So fell autumn rain, but all things must pass

So fell autumn rain, washed away all my pain
I feel brighter somehow, lighter somehow to breathe once again
So fell autumn rain, washed my sorrows away
With the sunset behind somehow I find the dreams are to stay
So fell winter

Answer 1

Firstly, you have misread the lyrics. It doesn't say 'so feel autumn rain', it says 'so fell autumn rain'. Fell is the past tense of fall.

'Though I was chosen'

You need to read the next line to help put it in context. Writing it as sentence you get:

'Leaving in twilight, though I was chosen to wander the way in the darkest of nights'.

So it's saying, even though I was chosen to wander at night, I am leaving in twilight (which means the late evening, when the light fades).

I find the dreams are to stay

This means 'I discover that the dreams will continue'.

As for the deeper meaning of all this, that's a matter of poetry and up to your interpretation. Or you could look up the song on a search engine and see if the artist has explained the reasoning behind the lyrics.