My daughter does yoga and loves it. Started at the age of 10 because doctors at Mayo wanted her to strengthen her muscles and help calm her down when pain hits her. She is in a kids yoga class.
Also a physical therapist would help too. Could try water therapy too. My daughter has a shirt that says I stress about stress before there is any stress to stress about. Mediation has helped her calm down. I took her to a salt cave last year for her Birthday and boy does that distress you. So relaxing. She bought me this best posture corrector as I sit for long periods of time.
I want to find someone who understands postures and make him/her work on my posture and teach me how to maintain it.
This can be a good Pilates or Yoga instructor, possibly a good PT or a fitness trainer (again a good one who knows and understands what the proper posture is head to toes).