Chronic pain patients constitute a large and heterogeneous patient group and it is important to build tools and methods that can identify efficient treatment options for each individual patient. It is estimated that 20-30% of the population has suffered from chronic pain and this imposes enormous costs on society and the national welfare programs. The research project Chronic Pain addresses the problem of how to provide patients and physicians with relevant, valid and adapted decision alternatives in a shared decision making tool. This paper presents the results from co-creation workshops early in the user-centred design process of the chronic pain mobile application. The end-users contributed in mapping the user needs and requirements, and made paper prototyping of the user interface. The main contribution lies on how a user-centred design methodology can be applied in a clinical development context.