Hey truck...my first trainer on the bench was John Kuc...see York Barbell hall of fame...he was incredibly strong...6-700 lb bench if memory serves.
If your sticking point is low in the movement your chest and back need to be worked on...if the sticking point is mid range and up it's front shoulders and tri's.
He had me do heavy close grips, weighted dips and heavy military press.
Tri 's and front shoulders were very important...and do not forget abs...they will help tremendously.
I'm only 5'7 , 185 and nearly 40 yrs old I'm still able to put up 385 and hope to be at 405 before the 40th b day in Sept. Let me know how you make out.