A Secret - Edited

Do you know the feeling?
The prickling pressure,
Right on the tip of your tongue.

It's a roaring beast, pawing to get out.
But you can't let it go,
It would leave you in ruins.

It's a fiery greatness, burning its way free.
A hole will soon be in your chest,
And your world, a mess.

It is as destructive as a cancer.
Killing you from the inside,
You want it out, you need it out.

I have a secret.
Deep within,
Would you like me to share it with you?

Nice work overall! I like the idea of the secret, and how you've used descriptive language to make that idea even more vivid. However, you have a few issues with grammar and spelling...

Right on the tip of you tongue.

Your tongue, you mean.

Its a roaring beast, pawing to get out.

This is a very common error. In this situation, it should "It's" since here it is used as a contraction of "It is."

A fiery greatness, burning it's way free.

And here we have the opposite problem. Here, it should be "its" because there is no contraction of "it is" in this line. Here the word shows the greatness's possession.

Also, the rhythm of this poem was somewhat disruptive because of too many periods. I think perhaps you should read the poem aloud and make some decisions to replace certain periods with commas. That will help the poem have less of a short, staccato rhythm.

A hole will soon be in your chest,
And your world, a mess.

The rest of this poem doesn't rhyme, so this approximate rhyme comes out of nowhere.

The last stanza came completely out of nowhere. It's in a completely different tone and viewpoint compared to the rest of the poem. I think that, if you introduced the "I" earlier on in the poem, it would be better. For example, the first stanza could be modified to: "This feeling I have, / do you know it, / this prickling pressure / right on the tip of your tongue?"

Another thing that you need to look at is the punctuation. It's not always correct, and this breaks up the ideas in this poem. A good way to make sure your punctuation is correct is to write your poem out in regular form, check it, and then put it back into poem form.

Something that you might want to look into is experimenting with your line breaks. Right now, they're logical, but boringly placed. Try getting a bit more creative and seeing how breaking your lines in different places alters the meaning of your poem. You might be pleasantly surprised. :D