Exercising when there is tightness can definately cause further stiffness and thus more pain. Kyphoscoliosis is an indication of fascial shortening in some areas, not uncommonly the psoas, and as this is connected to the low back, it commonly causes LBP. I try and test the strength of the hip muscles first to assess muscle balance, usually finding weakness in one or both hip flexion or abduction. This can be corrected by soft tissue work over these muscles (abdomen and anterior thigh in the case of psoas), and a return of flexibility in the sheath of the muscles often restores stremgth as well. The spine posture is altered by changes in fascial networks in the affected area, so I tend to go for this first, and release what I can. Then as a maintanance, give them some gentle stretching axercises they can do at home. Not too many as they either forget or get bored. Simple things like hip flexion, lunge stretch for psoas.