[Ayumi_lover]

Okay, If you mind what I think maybe I can explain

So we have

君に愛される程　胸が苦しいの
ねぇ私わ 君の事をもう...

君 - you
愛 - love
される - for する is only used for constructing the passive (される) and causative (させる) verb forms.
程 - ほど - extent
This particle is not so hard to use, but it has a particular pattern of use that
sometimes confuses people new to it. For this reason, it's probably easiest to say
that 程
ほど stands for 'extent' of actions, consequences, or even of properties.

胸 - chest
苦しい - hard, painfull

ねぇ - Hey
私 - me
わ - sa/yo/wa = the same in diferent levels
So 私わ it's a great possibility for girl to say that she broke up with her boyfriend because of her guilty
君の事 - person+koto - something about his mind, behavior, or etc.

を - direct objecter
もう - 'again', or also 'other', bot very reliable but google translates it as other

so my translation will be

"being loved by you, my chest hurts
I don't [love]... you anymore"




PS well I'm not fluent in japanese but only studying it, so just tried to translate, I have some experience in translating songs. Hope my version helped you and is right^^