Sometimes when i hear a word or touch a surface, the intense flavor of any food comes to my mouth, or even, i smell it. is this synesthesia?

Yes, synesthesia: Synesthesia is a neurological condition where stimulation of one sense (like hearing or touch) results in an experience in a whole different sense (like taste or smell). http://tinyurl.com/laea7qw (article has many additional references.) in people with synesthesia, the connections between different parts of the brain may be more myelinated than in other people's. http://tinyurl.com/cf7yesq.