Cultivating Activity, Commitment, Tolerance & Uplift Study - for Children With Chronic Pain

The goal of this clinical trial is to learn if the addition of physical exercise and mindfulness training, delivered by a mobile application, to multimodal pain rehabilitation could lead to a mor effective rehabilitation process and improved outcomes. The main questions it aims to answer are: Does 6 weeks of app-based physical exercise and mindfulness in combination with 6 weeks of multimodal hospital based pain rehabilitation give inferior results compared to 12 weeks of multimodal hospital based pain rehabilitation? Thus the study is an inferiority trial of a scaled down pain rehabilitation period with the addition of physical exercise and mindfulness training done at home with directions from a mobile application. Participants randomized into the active intervention will begin training for 6 weeks with the app, and continue through out the rehabilitation period. Those randomized into the control group will immediately begin pain rehabilitation as usual. All participants will wear an accelerometer bracelet for a week, before, in the middle and after the 12 week study period, and fill out a questionnaire and training logs.