Symbolism, Imagery, Allegory
Love is pain. That’s the long and short of Bella’s "hole" where her heart used to be. Of course she didn’t actually lose the squishy, pumping thing inside, but she did lose her "spiritual heart," so to speak. Since mind and body are connected, there you have the mess:
It was a crippling thing, this sensation that a huge hole had been punched through my chest… my heart must have been beating but I couldn’t hear the sound of my pulse in my ears; my hands felt blue with cold. (4.258)
When she meets Jacob, her hole eases up on her a bit, but when things go downhill with him, more holes show up:
I’d thought that Jake had been healing the hole in me – or at least plugging it up… I’d been wrong. He’d just been carving out his own hole… (11.235)
Finally, by the power of love, her hole magically disappears when she reunites with Edward:
I knew we were both in mortal danger. Still, in that instant, I felt well. Whole… It was like there had never been any hole in my chest. It was perfect – not healed, but as if there had never been a wound in the first place. (20.70)