Lyric discussion by foreverdrone 

Cover art for Surgical Focus lyrics by Guided by Voices

What happens when she "reaches out" to get into his head?

What happens is "the change."

There's a transcribing error here, which--however minor--causes significant meaning to be lost. It should read, "The change is not going to hurt you/Not this time."

"A change is not going to hurt you" sounds as pedestrian as, "Maybe a change will do you good."

But "the change" promises something more ominous.

So much so, she weeps. Why? Because she knows it won't hurt the first time...but what about the next, and the one after that, and...?

She requires deep uninterrupted thought (surgical focus) to get into his head, and thereby cause a change. Whatever that change is, the effect is so powerful, he's willing to wait in line "forever" to feel it again. "Until I get it, I can't breathe."

(Like, "I'm waiting for my man...first thing you learn is that you always gotta wait...")

This song is using science-fiction concepts about supernatural mental transformation as a metaphor: for addiction.