imo best way to bring up a weak point is to hit it twice a week for a while. obviously dont go as hard for each workout.. but being on a little assistance helps with the recovery. al,so note being on gear even a little means training more for a massive pump is much more effective than traditional 8-12 rep sets.
my advice is hit is twice a week, pump it to the moon and back and practice flexing it with that pump you get. mind muscle connection helps a lot with chest. also dont expect massive results immediately. keep consistent with your approach and it will grow over time. and if nothing else works just accept the facts youre presented with and dont stress it you still probably have a better chest than most
do something like
flat dumbbell bench work up to heavy set of 8 reps then drop weight by 30 percent and go for as many reps as possible dont even count. counting reps is pointless for muscle growth. use reps as a means to measure strength progress only.
then hit some hammer strength inclines just shit tons of reps and sets get your chest stupid pumped to the max.
then finish with dips to stretch the hell out of it do 2 or 3 sets and rep to failure nice and slow and deep (no homo).
between sets flex it by crossing your upper arms in front of you so the muscle is contracted and squeezing hard. really helps this one i found..
