I do not have a success story to share, because I hated my retainer and never wore it. However, as an adult, I have contemplated getting the invisalign (or whatever they’re called) braces that are like a cross between braces and a retainer, and they give you a new set to wear to progressively shift your teeth. Since you are having so much discomfort with the old retainer, it seems that your teeth have shifted more than you realize, so the progressive approach of the invisalign-type system might be better for you.