I used to have that same problem (of not having ideas) for most of my life. Now, I have more ideas than I can ever implement.

I would take a step back from startup ideas and read a book Become An Idea Machine[0]. I read it few years ago and in the beginning, it felt really stupid. Even after finishing it, I felt that it didn't really provide value. But over time, the process of forcing yourself to come up with ideas cumulates and suddenly you find yourself coming up with three ideas before breakfast.

[0]: https://www.amazon.com/Become-Idea-Machine-Because-Currency-...