Taking on extra responsibility is all well and good until someone figures out that they can just get you to do more work for the same amount of money. At that point your only option is to move on, because if you stop performing at the "expected" level due to lack of reciprocation, suddenly you have "performance issues".
The typical moves are: [1] Negotiate for more title, compensation at your current role (good outcome) [2] Leave for a better role (a good outcome) [3] Stay, no change, doing more work for the same money (not recommended)