If this is a qualitative study, then you need to use qualitative approaches for instance photovoice. These do not require a predetermined questionnaire. Please read more about the different methods of qualitative data collection
You may want to take a look at Work Extrinsic and Intrinsic Motivation Scale: Its Value for Organizational Psychology Research from Tremblay et al (2009). at http://selfdeterminationtheory.org/SDT/documents/2009_TremblayBlanchardetal_CJBS.pdf
You may also need to check the following link to the SDT webpage which is an excellent resource: http://selfdeterminationtheory.org/?s=SD+questionnaire