What I'm going to say is going to sound contradictory, but here goes...

You did an awesome job of communicating a deep, passionate truth in just one short stanza. However, it is still very wordy.

Your poem is packed with feeling that will really hit home with a lot of readers.

I love the prison metaphor that you introduced in the first line, and you should work to carry it throughout the rest of the poem. I also think you should focus on and make "the emotions" the subject of this poem.

Here are some suggestions that, in my opinion, would make the poem flow smoother and say more with out being “wordy”

I feel like a prisoner in my own body,
My emotions are me,
^
*you are not the prisoner, the emotions are, and they are what make you.

> Imprisoned in this body
> Emotions that define me

They need to escape and feel free,
My body just huddles them up,
^
*feel free is a bit redundant if you use the word escape, and the 2nd line needs a prison metaphor. I might actually flip the two lines and do this

> Locked up tightly in this cell
> Planning an escape to freedom

Squeezes them down,
And just cries them secretly out.
^
*“Squeezes them down” is covered in the idea of “locked up tightly”
So we just need to think of a prison metaphor to signify the release and put it into 2 lines.

> Crying secretly from my soul
> Emotions finally granted parole

Again, you have a great idea and did a great job.

~Ann

This poem is short, simple and sweet....
Great way at looking at it