Johto: National Park (1st in bug catching contest), Route 36 (Pokegear phone call) Or at the Pokeathlon shop on Thursdays and Sundays ( 2,500cp )
Kanto: Route 25 (Show Bill's Grandad a Growlthie (HG) Or Vulpix (SS) )
Sources: Serebii.net
fire stone
you can buy a action replay and do a cheat which you can get more than 1 fire stone
growlithe & eevee
fire stone
You can get a fire stone by taking part in the pokeathlon and then you can spend your prize points at the pokeathlon shop where you can get a fire stone.
everstone,waterstone dusk stone and fire stone
win 2nd place at a bug catching competition (fire stone or thunder stone 1st place sun stone)
In order of how he wants to see them (based on Heart Gold and Soul Silver): Gold/Heart Gold: Oddish - Leaf Stone Growlithe - Fire Stone Pichu - Thunderstone Jigglypuff - Everstone Marill - Water Stone Silver/Soul Silver: Lickitung - Everstone Oddish - Leaf Stone Staryu - Water Stone Vulpix - Fire Stone Pichu - Thunderstone
give your number to school boy Alan in route 36 then wait for him to call and he will give you a fire stone.
There is no specific place for a growithe to evolve. you just need to give it a fire stone
Growlithe can Evolve only with use of a fire stone. Fire stones can be won at the bug catching contests.
A heart of gold itself is an expression relating to someone kind. "They have a heart of gold".