It only targets either my Chest or my Shoulders.....Not Both

I'm barely on my frog stand right now @ 40s, and I find that if my arms are closer than shoulder width and if I squeeze my chest during the frog stand, then mostly my chest will be sore the next day. But if my arms are @ shoulder width or a little wider, and if I use only my shoulders to hold the weight then only my shoulders will be sore the next day and not so much my chest.

So how do I target then both with the frog stand? I know the planche progression is supposed to target almost all muscle groups, especially upper body. So am I.......

a.) only developing strength where I'm sore?

b.) developing overall strength even though some muscle groups may not be sore

c.) more advanced planche progression level will target more overall muscle groups

d.) incorrect form?

My chest is stronger and bigger than my shoulders due to previous bodybuilding isolation chest workouts. So now my chest is kind of ahead in the game while my shoulders are still weak. Help

First of all don't use soreness to judge what muscle groups you are working, all that means is weather or not that muscle is being used in a way it is used to. The answer is b.), c.) and possibly d.) though impossible to tell from without a video for d.). However you don't want to use a grip narrower than shoulder width so that you develop strength in a range of motion that will allow you to do things like L-sit presses to handstand and whatnot.