These chords were played mainly by the piano in the song, but I like playing it 
on the guitar too. :)

(Intro)
D Bm Em G

(Verse 1)
D                               Bm
     I could say that I'll always be here for you,

      Em                            G
But that would be a lie and quite a pointless thing to do.

D                                   Bm
     And I could say that I'll always have feelings for you,

      Em                            G      A
But I've got a life ahead of me, I'm only 22.

(Chorus)
G                   A                D
     Since you've gone I've lost that chip on my shoulder,

G                   A             D
     Since you've gone I feel like I've gotten older,

G                     A                    D
     And now you're gone it's as if the whole wide world is my stage,

G                     A                                       D
     And now you're gone it's like I've been let out of my cage.

(Instrumental)

(Verse 2)
D                                     Bm
     You always made it clear that you hated my friends,

      Em                             G
You made me feel so guilty when I was running round with them.

D                                Bm
     And everything was always about being cool,

      Em                                     G                 A
But now I've come to realise there's nothing cool about you at all.

(Chorus)
G                   A                D
     Since you've gone I've lost that chip on my shoulder,

G                   A             D
     Since you've gone I feel like I've gotten older,

G                     A                    D
     And now you're gone it's as if the whole wide world is my stage,

G                     A                                       D
     And now you're gone it's like I've been let out of my cage.

(Instrumental)

(Chorus)
G                   A                D
     Since you've gone I've lost that chip on my shoulder,

G                   A             D
     Since you've gone I feel like I've gotten older,

G                     A                    D
     And now you're gone it's as if the whole wide world is my stage,

G                     A                                       D
     And now you're gone it's like I've been let out of my cage.

(Outro)
D Bm Em G D