Flash is a TM in SoulSilver. It is given to you in the Bell Sprout Tower.
You can also buy it in the Goldenrod Department Store for 1,000P
I hate to be the bearer of bad news but you can not catch a Pokemon that already knows that as its an TM for soul~silver and a HM for the original silver.
That HM is not in the game. I'm sorry
ice path
go to jocose town
you get it on Route 36.
You can get the Hm flash of Pokemon silver is from the elder on the top of sprout tower in Violet city. There are alot of trainers through out sprout tower
There is a move deleter who can make pokemon forget HM moves.
you have to get hm whirlpool
It ain't a move its an ability.
HM 02 Fly is with the woman outside Cianwood City Gym.
HM 1=Cut HM 2=Fly HM 3=Surf HM 4=Strength HM 5=Flash HM 6=Whirlpool HM 7=Waterfall
You don't you have to use an Hm on a Pokemon