.Keys: That's gotta be the most weird topic title I've seen on GOG. :P
But its true. Thanks for the reminder.
On the topic of exercises allied with good postures:
A good exercise that helps to build up back muscle is plank:
https://www.menshealth.com/fitness/a46800165/what-muscles-do-planks-work/
It helps to avoid future back pain by strengthening the 'core' region muscles.
There are varied levels of planks and variations of the exercise too, which you should adapt depending on your age, resistance and weight.
(Please don't go jumping on the ground doing the hardest one otherwise you might hurt yourself, just a general rule to anybody reading anyway.)
Its not that hard once you start with small timings. 10s, 20s, 30s, taking breaks and making the time higher as time goes, with responsibility and understand your body.
Again: Depending on your age, resistance and weight. Do not force it if you can't. Start with 5s if needed.
I'm not that physical but when I started doing it, I could do 30s. After 2 weeks I could get to 1m, 2m and really felt the difference on back strength.
yes, the plank is king! though if you have weak shoulders other venues should be explored