I struggled with motivation for many years, primarily because I did not know who I was and what I wanted.
I read books like "Drive, the surprising thruth about what motivates us" and many more, but it was not until I read "start with why" by Simon Sinek I understood my "why" and finally became truly internal motivated.
Now I am more motivated than I have time and energy, but luckily I also have a guidance tool that helps me put energy into stuff that fuels me more.