I was going to offer you the stock adjustable angle 125mm stem I just replaced on my Giant for a shorter one but it appears you have a different type of steering head than mine//Edit begins here...but on 2nd thought?...I hafta agree with others here...that bike is just straight up too small for you and doesn't have near enough "Reach" to allow you to stretch out into a comfy position so you can relax the neck...maybe sell, trade or swap it out?

I think anything else would be an exercise in futility if not down right dangerous.