I have decent upper chest thickness (due in most part to chest usually being day 1 of my week, before my week gets busy and workouts derail).
I have very weak shoulders.
I am adding 45 degree side raises to address the very weak rear delts, and consistent BB shrugs to address the small traps (never a focus before).
However i have no idea how to improve the area where my chest and shoulders meet. Any training advice would be appreciated. thanks!
Side raises. And more side raises.
Don't forget about side raises.
The thing you need to do though, is to avoid cheating them, as you seem to have some traps, the true sign of guys going to heavy on the side raises.
Try seated side raises, and machine side raises. Leave your ego at home, and make sure it's the side delts that lifts, and not the front delts.
You could do some Seated DB presses as well, but mainly, make sure to work side raises.