There aren't achievements for ps3 they are trophys the same as achievements just you don't get points you have trophies instead instead of etting points you have to get trophies to go up levels on your id its that simple
Yeah Trophies are the same as achievments and it is true that entering some cheats blocks the ability to do side missions and trophys.
Thats why it is best to make 2 saves if you are going to cheat.