<C-o> and <C-i> allow you to go down and up the jumplist. They work with "jump" commands but not with jjjjjjjjjjj.
To take advantage of this feature — and save a lot of time and keypresses in the process — I'd advise you to get into the habit of using better ways to navigate through your code : /?^$fFtTbBeEwW{} and so on.
If you want to return to a previous location, first you have to mark that location using the mark (m) command, followed by any letter a-z or A-Z, like ma to mark a location as 'a'.