What is the problem with my screen it keeps going black.

It's quite possible the issue is hardware related and not software in which case it should be be examined by an Apple Authorized Service Provider or an Apple Store.

You can use this tool to locate one near you: Find Locations - Apple

Also here a link to Apple Support: Official Apple Support

Ria04 wrote:

My screen randomly went black, I’m so careful with my laptop not dropped it or spilled anything on it ever. It just randomly started going black a few days ago once I close it and open it the screen will come back even if only for a second. Some days it’ll go hours without doing it but it still eventually goes black sometimes with vertical lines on the screen. The screen has power but I see nothing the touch bar and everything still works if I add bright the black screen gets brighter, so I connected it to hdmi and the computer fully functions without issue. What should I do.

Perform this step If your iPhone won't turn on or is frozen - Apple Support

razmee209 wrote:

Ria04 wrote:

My screen randomly went black, I’m so careful with my laptop not dropped it or spilled anything on it ever. It just randomly started going black a few days ago once I close it and open it the screen will come back even if only for a second. Some days it’ll go hours without doing it but it still eventually goes black sometimes with vertical lines on the screen. The screen has power but I see nothing the touch bar and everything still works if I add bright the black screen gets brighter, so I connected it to hdmi and the computer fully functions without issue. What should I do.

Perform this step If your iPhone won't turn on or is frozen - Apple Support

Ignore my reply totally missed that the issue is with a macbook.