Overthinking something can cause you to ask questions and create stress over something that is not that important. For example: What is the answer to this famous proverb: What is the way to every woman's heart? If you overthink the question you could think, "Every girl is different, so is the answer based on opinion? Is the question literal or is it metaphorical? How long do I have to answer?" Etc... The answer is: Chocolate.

Sometimes when you're thinking about something, or trying to make some kind of decision, you keep thinking about it so much that you can create a negative outlook or imagine problems that may or may not happen. Most of the time, the negativity of the thought wins out and it can cause a problem that was not there to begin with.

The problem comes up because you think too much. There wasn't any problem but you create it by yourself.