Pain in neck and shoulder

Hello all

Like many, I’ve been working from home for a number of months and been hunched over a desk.
For much of the time, I stupidly used a small typist chair. As a designer/coder, I spent many hours on that chair and it’s had a harmful effect to my posture.

I started to develop a pain in my neck and shoulders. I just presumed this must be down to my poor work set up.

So I went out and spent an obscene amount of money on an office chair. After much research I chose to buy the Herman Miller Aeron chair. I have had the chair for about a month now and I still have the neck and shoulder pains. Is this normal after neglecting my posture in using such an unsuitable chair.

I do a series of exercises which help and ease the discomfort but I was hoping the pain would disappear, now that I have an ergonomic chair. Maybe I just have to be patient, but would appreciate any advice/comments.

Thank you
Sean