Mobile health (mHealth) interventions hold promise for chronic pain management, but suffer from high user attrition. Using motivational features to support users in adhering to their intervention has been a widely studied field, but their effectiveness in mHealth often varies due to a lack of standardised frameworks. This is particularly concerning for chronic musculoskeletal pain management, where poorly implemented elements could instil anxiety or promote negative coping mechanisms. Recognising this gap, we design an extensive list of 24 motivational features based on a recent framework, tailored for chronic pain musculoskeletal mHealth apps and conducted focus groups with health coaches and employees (potential users) to evaluate them. Results favour positive reinforcement strategies (i.e. praise, goal-setting) while highlighting concerns about pressure-inducing elements (time limits, leaderboards). Participants also emphasise the need for careful information presentation to avoid potential catastrophising and the importance of privacy when considering social features. Our findings offer initial guidelines for the ethical and user-centred implementation of motivational features in chronic musculoskeletal pain mHealth interventions.