Chosen Solution
When I press on the screen with both of my thumbs, the screen returns to being totally normal, but take a little pressure off and it’s black/lined again. What does this mean and can I fix it.
The screen needs to be replaced. Here are guide and parts from iFixit on how to replace it: MacBook Pro 15" Retina (Mid 2015) Display Assembly MacBook Pro 15" Retina Display Mid 2015 Display Assembly Replacement
It doesn’t matter if your screen works like normal when you press it. The screen cannot be taken apart without totally destroying it, so you can’t fix the screen even if you know what went wrong. Just replace the screen.
