Chosen Solution
I have a bad habit of dropping my phone in between my legs. This morning, I did that and I was blessed enough to have my legs spread apart just enough for my phone to fall through. Now when I try to use it, the screen flickers from normal to green tintish every half second and stops responding to touch after awhile until I lock it and unlock it again. Is there anything I can do other than replace the screen? The phone is out of warranty.
This is almost certainly a screen issue. A new or known-good screen is also the first step to troubleshoot screen issues so you will not have a choice but to order a replacement screen from a reputable supplier. I would suggest this one.