Hey man, I have pretty good chest development, so I'll share with you what worked for me.
Do regular pyramid sets of 12-10-8-6 and then a pump superset of 12-12(sometimes reverse pyramids to change it up and stimulate growth.)
Start with lighter weight and gradually add up to what you think you can do for 6 hardcore, nearly failing reps.
Then with the pump superset, do light weight for 12 reps on the bench again, then do some flyes at a light weight IMMEDIATELY AFTER for 12 reps. This should pump your pecs pretty well.
I usually do 3 to 4 workouts for chest in a routine. Heres an example of my routine for chest:
Bench press(Pyramid and pump-set with Dumbbell flyes at the end)
Incline bench(Pyramid and pump-set with Dumbbell press)
Pec-Deck Flyes(Pyramid and pump-set with Dumbbell flyes/Press)
That should help you out a bit man.
Also remember to eat 1.5g of protein per body weight.
And remember man, if you're natural, muscle grows slow! An inch takes some guys 3 to 6 months on one bodypart! And changing up your chest routine now and then helps stimulate growth.
Keep pushing man and you will have success.
hope i helped