Hoping to cut down on shoulder pain from new DIY build

My mattress currently consists of

Lux High Quality - 4" 2.8lb density 50lb firmness
HD High Quality - 1" 2.8lb 35lb firmness
Dunlop latex - 2" 30 ILD firmness
Super Soft - 1" 1.2lb density 12lb firmness
2" Memory Foam 3lb density 15lb firmness

I’m 200lbs and a side sleeper, wanted a firm base because I know from past overused mattresses I’ve had I really don’t like when my hips sink too much. With this current set up everything feel great except the very top of my arm at the shoulder. There’s too much pressure concentrated on about 2" of my arm there.

Is there anything I can do to alleviate that with the current layers I have, or should I try adding another inch or 2 of something? Also, as a side note, my girlfriend finds the mattress extremely comfortable, but she weighs much less and has narrower shoulders.

I would recommend 2" of Soft #19 Talalay latex to help with those issues - 2 " Blended Talalay Latex Mattress Topper , Talalay & Dunlop Latex Toppers - Bare, Latex Mattress Toppers and Cores, All Products It will also give you better air flow than those memory foam layers. Let me know if you have any questions.

Would that be instead of the memory foam layer, or placed on top? Also does talay latex provide support to keep from bottoming out as much as the 15lb memory foam?

Try it both ways. Memory foam has no support. Look for my article here on MU “Why Sink When You Can Float”.