Messi's position is forward. Is it correct to say his role is forward? Do position and role mean the same thing?
I'm basing my answer on years of watching soccer while not paying too much attention what the commentators say, and not any official lingo. As a disclaimer, I never played organized soccer either. But you can take a look here and here which aligns with my answer.
Position is, well, the actual position the athlete plays. Examples are goalkeeper, center back, attacking midfielder, etc. These represent specific location players are responsible for covering, and supporting teammate around them, and handling oppositions. Positions are highly coupled with formation of the team. In a typical 4-4-2, the back 4 are the defenders, middle 4 are the midfielders and the front 2 are the forwards. Also jersey numbers are traditionally related to the position of the players.
Roles are what you're supposed to do as a player. For example, some forward positions (using forwards as the OP's question mentions it) include center forward, striker, winger. The roles of these players are to score, and to be in and create scoring opportunities. Similarly, the role of a defender is blocking shots, intercepting passes, helping the goalie to protect the net, etc.
Also note that the captain is role too, where you're responsible to handle communications with the referees and being the overall leader of the team on the pitch. You could also be a fielder of any position and have taking free kicks or penalties as one of your roles, if you're more skilled than your teammates.
You can think of the role as the duty the players are assigned, and the position as the location/territory they're responsible for on the pitch during open play.
Now as a fan I'd argue that the term role can be used even more loosely. For example, Xavi and Inesta where called conductor or composer on Barcelona and the Spanish national team. Composer or conductor don't define a duty in soccer terms, but they convey to the audience that the player labeled with those adjectives are those that the flow and tune of the ball movement goes through, they're the ones with exceptional visions that can bring art to the sport. Or you hear that player X is the heart of the team, an example being Vincent Kompany during his time on Manchester City. Again, this doesn't define a duty or position either. But when a player is marked that, if you seen them fight hard for the ball or play with emotions, their teammates are also elevated on the pitch. Or when they play uninspiringly, the rest of the team suffers lack of focus and discipline. Although these unconventional roles don't define a specific duty on the pitch, they do describe a reliance for the individual in the team.