It might not fix the neck pain depending on why you’re experiencing the pain. You should definitely give a shit about your posture though. Your spine is responsible for keeping your whole upper body upright (along with your abdominal muscles and some others). Neglecting and mistreating that is not a good idea long term.
That’s why you see jokes about old people and their backs or memes that are like “Welcome to your 30s. Here’s some advil for your pain. Have a nice day.”