The whole song is super easy! It just repeats G, A, & C! It sounds better with a 
capo on 2, but you don't NEED to use a capo. :)
G             A
Na na na na na
C            G
Na na na na na
G            A
Na na na na na
C          G
Na na na na

G                                              A
When you know some stupid boy's just trying to break your heart
C                        G
Don't even play his game
G                               A
He doesn't see how beautiful you are
C                 G
Baby just walk away

G                                            A
When you're feeling like the world is pushing on your chest
C                      G
Don't let it get to you
G                                A
Sometimes you gotta step back and take a breath
C                             G
Find a different point of view

G             A
Na na na na na
C             G
Na na na na na
G           A
Na na na na na
G                           
When your heart's about to break
             A
Sometimes you just gotta say
C          G
Na na na na

G                                         A
When you need to get away from the place where you are
C                            G
Sometimes you gotta hit the road, baby,
G                            A
Turn the radio up, windows down in your car
C                      G
Take a trip and let it roll, roll, roll, yeah

G            A
Na na na na na
C            G
Na na na na na
G            A
Na na na na na
G                        
When your heart's about to break
              A
Sometimes you just gotta say
C          G
Na na na na

G                                   A
When it feels like all the walls are c-c-closing in
C                                 G
And the noise is way too loud for you
G                                A
Put your headphones on and get lost in a song
C                           G
Gotta find you a different crew
C'mon, C'mon
G
Yeah, from the top, here we go, c'mon
G            A
Na na na na na
A           G
Na na na na na
G           A
Na na na na na
G                          
When your heart's about to break
                  A
Sometimes you just gotta say
C         G
Na na na na

G           A
Na na na na na
G                                             A
When you're feeling like the world is pushing on your chest
C                     G
Don't let it get to you
G                                     A
Sometimes you gotta step back and take a breath
C           G
Na na na na