if you have been doing those same lifts for the entire year then you need to switch it up. mix it up. throw in some barbell exercises, hammer strength, machines, cable crossovers. it's all about switching up the type of tension you are putting on the chest. you need to switch that up so your body doesn't adjust to your workouts and know exactly what to expect each chest day. list out your rep scheme so we can see how heavy or light you are going and just accordingly.
also as goes without saying, you may not be eating enough and basically in a maintenance mode where you're not getting enough calories to increase your strength.