Blue Flare was Fire-Type move but, Blue Flare was the signature move of Reshiram as you know. Only Reshiram and Victini (Obtained in Event on Pokemon Center Tohoku Victini that can learn Blue Flare ). But, unfortunately the event of the Victini was ended. But, sometimes in the future you will got new event of victini and the others.
Maybe, that was another "Pokemon Bug" (not bug Pokemons I mean, some kinda error or self-glitch) But, your Litwick can learn Inferno and Fire Blast the Powerful fire moves. for Inferno is at Level 38 and, for Fire Blast, from TM. of course litwick can learn Inferno and Fire Blast