The Argentine says reports he has lost his passion for the game and might be open to a move away from Camp Nou are untrue.
Both the Argentine's form and attitude have been openly questioned during what has been a difficult season for the Blaugrana, with some reports suggesting the 26-year-old could be tempted by Manchester City's alleged interest in his services.
However, Messi says he remains content at Barcelona and lashed out at the media for fabricating stories about him.
“A lot of things have come out in the press over the past year, and practically all of it is nothing but lies. I am fine,” the four-time Ballon d'Or winner told reporters.
The forward's sole focus is now on helping Barcelona retain its Liga title, which looked all but lost after last weekend's 2-2 draw at home to Getafe.
However, Atletico Madrid's subsequent loss to Levante, coupled with third-placed Real Madrid dropping four points in the space of four days, means that the Blaugrana's destiny is now in their own hands once again.
Indeed, if Barca beats Elche away this weekend, Tata Martino's men can then clinch the title by defeating Atleti at Camp Nou on the final day of the season.
“We are in a much better position now than we were a few weeks ago,” Messi said. “There is a real possibility that we could win the league; it’s down to us. Winning the league depends on us alone; we have to make the most of the situation – we cannot let this chance slip away from us."
Barca currently trails the Rojiblancos by three points but given the teams' draw at the Vicente Calderon earlier in the season, a win for the Catalans would see them crowned champions on account of a superior head-to-head record.