Well, my listening still needs work, I got most of it but I did have to look up the lyrics for a couple of points. あっても -still- sounds like あらても to me even after looking it up, but ah well.
Anyway, this translation is very awkward and unpoetic. I tried to be as literal as possible since you say you're trying to learn Japanese.
This is a pretty good song to learn from, actually; it doesn't have terribly weird grammar that you only find in songs and poetry, and all the vocabulary is common (except maybe プラトニック, but that's a loan word anyway, and this is not the first song I've seen it in.)
なぜか かなしいことが
あっても
わらってみせる
あなたをみてた
Even if for some reason there were sad things, I saw you show me a smile.
"not found" ah...
まるで しらない きもち
"not found" ah....
Completely unknown feeling
あなたが くれた
たくさんの メモリー
The many memories that you've given me
ゆれる こころ プラトニック
あふれだしてく おもい
A shaken heart, Platonic,
Overflowing feelings
そうよ それは
ただ あなたの こと
すきと いう きもち
Oh yes, those are simply the feeling of loving you.
もしも つたえられた なれば
あした わたし すこしは
かわれるの かな？
If I could convey that to you, I wonder, would I be able to change a little tomorrow?
あなたと おもいで
かさねていけますように
いのってる uh
I pray to be able to go on accumulating memories with you. Oooo.
