Assuming that data given are splitted by space rather than tab's, Here is my try.

use strict;
use warnings;
my @result;
while (<DATA>) {
    s/\s*$//;
    my $line = $_;
    if (m/[A-Z]/){
        my $next_line = <DATA>;
        while (m/^|\s+/g){
            my $pos = pos;
            my ($key)=$line=~/^.{$pos}(\S+)/;
            my $value;
            if ($next_line=~/^.{$pos}(\s+)/) {
                $value="";
            }
            else
            {
                ($value)=$next_line=~/.{$pos}(\S+)/;
            }
            push @result,[$key,$value];
        }
    }
    
}
@result = sort {$a->[0] cmp $b->[0]} @result;

print join ',', map {$_->[0]}@result;
print join ',', map {$_->[1]}@result;

    



__DATA__
A1             
9198 

B1   C1                          D1       E1    F1     
23   232                                        233     

G1                               H1        I1     
2222                                       323
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