Costa has been regularly linked with a move away since joining Chelsea from Atletico Madrid for £32 million in 2014, and said last month that he tried to force though a return to his former club last year.
The Spain international was dropped by Chelsea coach Antonio Conte in January following a training ground row with a fitness coach over a back injury at the time of a lucrative offer from Chinese Super League club Tianjin Quanjian.
Costa, 28, has refused to rule out the possibility of a move there at the end of the season and said:
“I have two years of my contract left.
“I am always very honest with the people around me. I always say that I am very happy at Chelsea.
“The club do a lot for me, the fans, my teammates and this is a winning team, which motivates you to be there a long time more.
“I’m happy at Chelsea. But I’m not saying I’m happy with my life in London, because that is something totally different — the one thing has nothing to do with the other.”
Costa said the views of those who see him as a confrontational and indisciplined player did not bother him, adding:
“Sincerely, I couldn’t care less.
“The people who do not know me can think whatever they want. It is not going to change how I am.
“I am a good kid, a happy kid. If the people who know me said anything different, said I was a bad kid, that would hurt me. Wherever I have gone I have always made friends, always been loved.
“So if the people think that it is due to the media, who speak a lot of s—, always talk nonsense. That is where that image comes from.”
Costa has scored 18 goals in 34 appearances in all competitions to help propel Chelsea to a seven-point lead at the top of the Premier League but has struck just four times in 12 games since the January incident.