This is actually a really simple song; it's just G, D, Em and C throughout the whole song.
First verse for example:
G D Em C
There's so many memories, muted in your pillow
G D
Tattooed on your wall
Em C
They've seen it all and kept it in
G, D, Em, C
(same on the next verse)
G D Em C
If Only, If only, If only your bed could cry
G D Em C
If only, If only, If only your bed could cry
(and so on)