I interpret this song to be about how a person feels lost and lacks in self confidence. This could be; not having the assertiveness to be themselves or not being able to express their feelings and/or opinions in a manner in which they usually would.
"Alone...alone" Being alone - negative consequence of the way you conduct yourself.
"How the strings become the stitches in your mouth" - possible connotation of puppet strings and feeling manipulated by others around you, causing you to feel insecure and in turn not being able to express important emotions/feelings/opinions etc.
"Your growing imagination preparing you for what your heart requires to say" - trying to comprehend how to articulate your thoughts and emotions but feeling overwhelmed at the same time.
"You're worth more than this" - you know you deserve better.
I'm not saying this is 100% dead on, everyone interprets things differently, which in turn is the beauty of it.