Exercises to get a flat back posture?

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 Hey guys, I don't actually want to develop a flat back syndrome (sorry if the title led to this conclusion). But my spine is very arched and everybody notices that. Maybe it's just my natural curves that are too much but it doesnt look great. I would like to improve it in order to have a better posture or just to look a bit better.

I am a software developer and was a gamer as a child, so maybe it has something to do with my current spine shape. I actually went to a doctor last year and he said I have scoliosis (not too much, I could see it in the x-ray) and I am arched forward (he said it is worse in the thoracic region, but my lumbar doesnt look good at all, if I stand against a wall I can slide 2 hands between the wall and my lumbar)

Have you tried any workout/stretching routine to improve your spine/posture? Did it work? Would you recommend something?
And what about the scoliosis? Have you tried or heard about exercises/techniques to reduce the 'S' shape of the spine (mine is very small but I still would like to do something for it)?

Any help is appreciated!

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You have to see a chiropractor,  they can prescribe exercises for you.

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Deadlifts, Barbell squats, and back bridges would be great for developing a straight back. I've been doing them for about five years.