Where can I get more incenses in HeartGold?

Question

In my Pokemon HG I sold them all, so will or can I get some more? And why do we need incenses to breed Pokemon?

Answer 1

If you sell all of them, unfortunately you are unable to get any more. As for why you need them for breeding; that's just the way the game is, there is no real explanation. Game Freak has chosen to put them in the game and to breed certain Pokemon you require them.

Answer 2

As Saz said, you cannot get the Incenses again in-game, there is no place to buy them. You will have to trade them from another game.

The reason that Incenses are needed to breed Pokemon in Generation 4 is because the baby Pokemon were introduced in that Generation, their "adult forms" were already available in previous generations.

It wouldn't really make sense to for example breed a Snorlax in Gen 3 and get a Snorlax, but breed a Snorlax in Gen 4 and get a Munchlax. So that's why the incense is required.