Heaven was a mythological paradise in many cultures. The term could also by synonymous with the sky.
Since ancient times, Bajorans have believed that the pagh of the faithful will "walk" with the Prophets (who reside in the Celestial Temple) after death. (DS9: "Emissary", et al.)
In the 17th century, John Milton of Earth wrote in his poem Paradise Lost that "It is better to rule in Hell than serve in Heaven." (TOS: "Space Seed")
In the 22nd century, Kai Taluno of Bajor claimed his ship was "almost swallowed by the heavens" near the Denorios belt. In fact, he had witnessed the opening of the Bajoran wormhole. (DS9: "Emissary")
In 2366, Geordi La Forge stated that he hoped the non-corporeal Koinonians invading the ship's systems wouldn't "blow us to Kingdom Come while (they're) figuring out how to blow us to Kingdom Come." (TNG: "The Bonding")
Heaven was discussed in the Albert King song Everybody Wants to Go to Heaven, which remarked "Everybody wants to go to heaven, but nobody wants to die". (Star Trek Into Darkness)