If you're stuck on something

If you're stuck on something, ask someone to interview you on the topic.

Or talk to someone about it.

They might not know the answer. More like, they will not know the answer. But, this context change, when you're out of your head, might be enough.

If not, and the problem is more complex, then you might need them to ask you pointed questions. Which would then help you clarify your thinking.