Keeps Pounding Against Walls

I feel this pain in my chest
so I try to rationalize it away:

this isn't heartburn,
my arm's not tingling,
it's not a heart attack

but I think I know
that my heart's been pounding
because my heart's been trapped

it's been trapped
& I don't know if it's trapped by my ribcage
   I don't know if it's trapped by your male oppression
   I don't know if it's trapped by my cowardice
                                             or my fear

or by--

I don't know what trapped my heart
but it's been pounding so hard

so hard that it's slamming on those walls
those god-damned walls that I can't even see

god, I don't even know about the walls
but my heart keeps pounding against them

I don't know about the walls
but my heart's still pounding