Designing learning experiences for students is a key responsibility of teachers. This involves designing stimulating and engaging tasks, selecting and creating appropriate resources, and deciding how best to support students to successfully complete the tasks. This is a complex process in which many factors need to be considered. Learning design research and tooling is focused on how to support this teacher design work. Existing learning design tools support the authoring and sharing of learning activities, which -if represented computationally -can also be enacted in virtual learning environments. An important part of the learning design process is thinking about what it is that students are to learn. This then informs the design of the learning activities. However, research on how to support this early phase of the learning design process is scarce. Indeed, an emerging finding from research investigating teacher design practices is that teachers' design work exhibits some characteristics synonymous with the broader field of design. Specifically, teachers formulate and work with a design problem. But, teachers generally don't consider their work in terms of design. Thus there is scope to encourage and support design thinking in teachers along the whole learning design process, including in the initial phase of identifying a design problem. This paper reports on a pilot study where a learning design Problem Generation Tool was created, in the form of 20 stimulus questions, to generate deeper thinking about the design problem. The stimulus questions are based on 3 foci, which are to be considered in an iterative way to think about and generate the problem: Understand the nature of the design problem and your goals (e.g, What kind of problem is this? Why is this design being done?) Map your context (e.g., Who are the students? How will the course be taught? Who will teach in this course?), Plan your design approach (e.g., What preparation do you have to do? What is your initial plan or steps you will follow for your design process?) The tool was incorporated in the Integrated Learning Design Environment (ILDE), a community platform that integrates a number of learning design tools supporting conceptualization, authoring and implementation of learning activities. The Problem Generation Tool integrated in ILDE was used with eight participants, who were already familiar with ILDE, in a workshop setting in a postgraduate program at a local University in Barcelona, Spain. Participants had between one and five or more years of teaching experience. Results showed that participants found the Problem Generation Tool helpful. The level of perceived usefulness by question varied across participants, while a few questions were not sufficiently clear and need to be revised. Overall, there was evident elaboration of the participants' design problems thus suggesting design thinking was stimulated and identification of the design problems scaffolded.