There is a mistaken belief that creativity means being completely free and unfettered. There should be no restrictions or barriers. This is as mistaken as the belief that creativity is just being different for the sake of being different.
Creativity is easier if there is some structure. On the other hand, if the structure fixes some point, then that point can't be altered.
'I want you to write a book with aliens in it'.
'I want you to write a book with aliens in it who all behave like dizzy blondes'.
The apparent restriction of the second request actually makes creativity easier. The answer might be to express the request or objective in different ways. Some of the ways have a structure and others do not.
Generally speaking, exclusions force a bigger change than inclusions. If you said you wanted a new game of football which didn't use a ball, then your thinking would have to go much wider.
If you said you wanted a new sport which didn't have a limited number of players in each team, then you would need to think rather hard.
You can ask for a very small change. This could be designed to solve a problem or put right what is seen as a deficiency. In these cases the 'inclusion' covers practically all the existing situation except the area where the change is sought.
So when does creativity become problem-solving - and the other way around? There is sometimes a lot of overlap. If you are looking for an idea to solve a particular problem, then that is problem-solving. If you are looking for a way of speeding up the checkout process in a supermarket, then that could be problem-solving. If you are looking for a way of making the checkout process more enjoyable, then you might think of types of entertainment or ways you could chat to others in the queue, etc.
The only reason for separating problem-solving from creativity in general is that with problem-solving there is a specific problem that needs solving. With creativity there is an area in which new values are being sought.
The new value could be open-ended or might also be specified: 'I want a better way of doing this', or 'I want a much quicker way of doing this'.
If the process was indeed quite slow, then this becomes problem-solving. If the process was not especially slow, not slow enough to be a problem, then the goal is a new value.
The distinctions listed here perhaps seem philosophical rather than practical. But creativity works best when it is applied in a disciplined way. You need to know what you are attempting to achieve. It is necessary to have a very clear idea of the task. You can indeed vary this or set yourself multiple tasks. At any moment, though, you need to know what your creative task is.
Rather from limiting creativity, the introduction of restrictions and focus actually enhances the process. Furthermore, every new idea feeds into other new ideas in a continuous process.