An illustration of your problem:
your weight training may improve or worsen the problem.
It depends on which exercises you do and how you do them.
First thing is you want to "stop" training your chest.
That is "stop" doing bench press. When doing bench press use a narrow grip that shifts the load onto the triceps muscles instead. Prefer (...
Used to have rounded shoulders, extreme lordosis and nerd neck.
Fixed everything just by doing weighted planks for one month.
It is counter intuitive but if you study the anatomy of the human back you will understand that the trapezius muscle and the roumboid muscles are among the most important when it comes to holding a plank.
Why? In summary, because ...