I feel severely under-stimulated. Any advice?

I was born and raised in a major dynamic city in Africa. Over 20 million people. However, I came to Germany a few years ago for work and I live in a city with just over 600,000 people and I am struggling with the adjustment to the much slower pace. I feel severely under-stimulated and "dead inside", for lack of a better phrase. I am considering moving to Berlin but I worry that it may not make that much of a difference. Anyone has any advice?

EDIT: The comments have been amazing. Most, atleast. Especially great to know others feel this way and have ways to label it/manage it. Danke an alle!