my $line = <DATA>;
my @wanted_substrings=();
#No Problem
#my $StartTag='START';
#my $EndTag='END';

#Error Unmatched ) in regex; marked by <-- HERE in m/TRicky\(.*?)
#my $StartTag="TRicky\\";
#my $EndTag="\\endTricky";

#No Error but no value VALUE
#my $StartTag="Next\$";
#my $EndTag="\^Next";

#No Error but no value VALUE
my $StartTag="Last\+";
my $EndTag="\+some";
 	  if ($line=~/$StartTag(.*?)$EndTag/g)
    {
       push(@wanted_substrings,$1) ;

 	  }
print join "\n", @wanted_substrings;
__DATA__
CharSTARTanotherENDCharTRicky\VALUEE\endTrickyNext$VALUE^NextLast+VALUE+some

##</code><code>##

#Forgot to mention if I do not use $StartTag or $EndTag
# and insted use actual string that it will work.

#Instead
 	  if ($line=~/$StartTag(.*?)$EndTag/g)
#This one works
 	  if ($line=~/TRicky\\(.*?)\\endTricky/g)
#Problem is that I have to use varialble $ because 
#I am using it as an arg in my sub

sub getInfoFromSingleLineMultiLineFile
{
#$stag,$etag uses as arguments
    my ($InputFile,$stag,$etag)=@_;
    my ($line,@wanted_substrings);

    #Openning file for reading
    open(IFH,"$InputFile") || die "Can't open file: $InputFile\n";
      while($line=<IFH>)
      {
        if ($line =~ m/$stag(.*?)$etag/g)
        {
           push(@wanted_substrings,$1);
        }
      }
return @wanted_substrings;
}