In perl, I would create an array of questions, each array element holding a reference to a hash:

my @questions

# a question from the Tasmanian Devil
push @questions, {id => 1, text => "Why for you want to bury me in the
+ cold, cold ground?, show => 1};
# etc.
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Note here that QUESTION_NUM is just the index in the array plus 1.

Then inserting a question after question 10 is a simple matter of of a splice:

# Maxwell Smart?
my $new_q = {id => 9, text => "Shall we use the Cone of Silence?, show
+ => 1};

splice @questions, 9, 0, $new_q;
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For references to other questions, just add a reference => $quest_ref element to the hash.