Remember the Closed Gym at the start of the game, the one in Viridian City? Well, if you have gotten the other 7 Badges you can challenge the Gym Leader...
I won't spoil the Gym Leader but you have seen him 3-4 times and he is a "master' of ground type Pokemon so Pikachu's Electric attacks won't work.
You have to beat all of the other gyms otherwise it's impossible.
the gyms are in the citys but some are harder to get into than others
Uh.. Pokemon Volcano? I never thought there were a Pokemon game like that...But you can find gyms in some city's,but not in towns.
The answer is... No there are no and i repeat NO hidden gyms on Pokemon soulsilver (but there are more gyms in kanto which you can get to by the boat pass from prof elm after you defeat the champion)
no
Once you beat the other seven gyms, the final one will unlock. This is the same for Pokemon Red, Blue, Yellow [including the Special Edition] and Pokemon Red/Green.
when you beat the gyms you get badges that let you use hm moves in the field and stronger Pokemon will obey you.
No, it has 16 gyms. 8 in Johto and 8 in Kanto.
keep beating gyms
Pokemon HeartGold, SouldSilver
eight.
16