A sonnet

[dukealien]

A song of love unsung,
a melody of tears,
a symphony of longing
a tune that no-one hears.
 
A tale of love untold
waits sadly for an end,
the narrative not written,
still waiting for the pen.
 
A verse of love unrhymed,
no metaphor in place,
some lines that have no meaning
will now all be erased
 
I saw you with your chosen one,
all hope for me is gone.

This is nicely apophatic (a word I learned from Milo only recently) - it describes by negation.  This would have been difficult in the final couplet, but what you did there has much that effect, too.

It's also an intriguingly minimalist sonnet - iambic trimeter rather than the usual pentameter or even tetrameter (aside from line 13).  The rhyme scheme is also spare, ABCB rather than ABAB, and the final couplet is an eye-rhyme.

None of that is bad or wrong:  the effect (to me) is the tragic minstrel or jilted lover choking or sobbing over his loss.  He overdramatizes, perhaps, but he's definitely feeling it and going on (rather) about it in at least temporary sincerity.

So, the technical notes up to here are not important.  There are, however, a few things that could stand thought and improvement.  First, it's very static - in particular, while stanzas 2 and 3 are complete sentences (though passive), the first stanza is  entirely sentence fragments - not even "is" for a verb.  There's certainly room for one in four lines with only one B rhyme to be found:  make it active, a grabber to get the reader's attention.

The B near-rhyme in stanza 3 is not bad, but could be closer.  The final couplet, though, could stand work.  Yes, line 13 is drawn out like a final sigh before giving up at the end, and it works for that, but between this and the eye-rhyme it's a good final idea but lacks punch otherwise.

Which leads to the final criticism of that last couplet (and, perhaps, the third stanza, too):  ideally, a sonnet should have a turn - a new idea introduced unexpectedly which redirects the course of the piece.  It could be that bringing "you" into it at the last is such a turn, but perhaps the idea of a person rather than the continuing catalog of concepts could be introduced earlier.

In basic critique, don't take any of the above too much to heart.  It's a good poem, and the cut-down sonnet form is suitable for its theme and project.