Hard drive of my 11 pro is broken. How much if I want to replace a new hard drive in my phone?

Since a fall damaged your iPhone, Apple will not replace the motherboard in your iPhone. You can however, purchase an out of warranty replacement for your iPhone, which will run you about 60% of the cost of the phone when new. Schedule an appointment at your Apple Store Genius Bar for evaluation and options.

We are not Apple. This is a user to user only forum. As I recommended above, schedule an appointment at your Apple Store Genius Bar and apple will explain your options. Typically, they won't replace such parts. They will most likely offer you an Out of Warranty Replacement phone. But again, we are not Apple, so you need to get support directly from them.