I switched pillows and now I can’t tell if my neck or my mattress is the problem

I didn’t plan to rethink my whole bed setup, but here we are. I tried an ergonomic pillow and suddenly my neck feels… different. Not worse. Just impossible to ignore. Same bedding. Same sleep position. Same mattress I’ve been fine with for months. But once I wake up, I can’t tell what’s off anymore. Is my neck not supported enough? Or did the pillow just make me notice my mattress in a way I never did before? Maybe “ergonomic” only works if everything else is already perfect. Anyone else change one pillow and end up questioning the whole bed?