Guide yourself from a kyphotic sitting posture to an upright sitting posture by anteriorly rotating your pelvis and increasing your lordosis. Then let go 10% and maintain this for a few minutes. Initially it might give you some new pains which should subside in a week's time. if these do not help you, do let me know and I will try to locate someone close to where you are, so that you can be mechanically diagnosed and helped.
Asha