I'm not sure what your goal is...

We have to guess how '$token' and '$line' look like, and I have no idea why the (undemonstrated) while loop should not terminate.¹

(see How (Not) To Ask A Question and How do I post a question effectively?)

But pos will tell you where the last match paused, the rest should be easily calculated with 'length($token)' (IF token is just a simple string)

  DB<127> $str= "a  b  " x 4
 => "a  b  a  b  a  b  a  b  "

  DB<128> $token="a"
 => "a"

  DB<129> print pos($str),": $1\n" while $str =~ /($token)/g
1: a
7: a
13: a
19: a
[download]

update

¹) well except the fact that lc always creates a new string which resets the search-position. Simply lowercase once '$line' before you loop!