i totally aggree with the above , most often , people asking for more inner pecs simply have not enough pecs to do so .
once you reach a certain overall mass , you will have inner pecs, simply .
and IMO , the best for it are pressing mvents ( i know i go against the grain here ) , but , for me , using the smith machine and rotating pressing motion from incline to high incline did help .
i get the stretch after , while doing a stretching loaded a la dc .