macbook pro screen going black after shut down

Hey. Ever since I plugged my MacBook Pro into a external monitor it has started to go black after I turn it on from shut down. After a few hours of my Mac being shut down I come back to it and turn it on it launches fine and takes me to my desktop after a few seconds however the screen turns off and is unresponsive. I have to hold down the power button and the fan turns off and then I have to wait a few seconds and hold the power button on again to turn it back on and the second time I turn it back on it doesn’t go black so I think that my Mac stays on however the screen is black but I have had this problem for about 6 months now and I do not want to have to erase my whole Mac to just fix this issue so I am just wondering if anyone has any suggestions on how to solve this issue I am facing.

this issue isn’t much of a big deal but is annoying to have to do every time I turn my Mac on especially that it did not do this before. I would appreciate any help anyone can give and I am willing to try any solution that you come up with that isn’t erasing my Mac.

thanks, Zak.