Devil on my Shoulder

Devil on my shoulder,
told me, throw a boulder,
destroy the window,
like our relationship,
bring you so low,
end our love trip.

Devil on my shoulder,
made my heart much colder,
and river is like time at all,
so I become much older,
but I still waiting on a waterfall.

Devil on my shoulder,
said me it's all over,
there's No longer, WE,
it's only you and me.

Devil on my shoulder,
wish I was a pain holder,
but I found an angel in my heart,
who showed me the true beauty art.

Who is behind your shoulder?
A Devil,an Angel who is the beholder?