I had this issue as well. My phone seemed to have a micro bend. Using both hands I applied a minute amount of pressure across the frame of phone to test my touch capability (Be very careful and use common sense). At certain point my screen started responding. However, when I released, it would stop working. At that point I knew that it had to be a faulty connection. I opened my phone, unplugged LCD screen from main board, cleaned all connections and inspected them for damage. I then put the phone together taking extra care to make sure all of them were snug. Put it all back together and luckily everything seemed as it should be. I was lucky and it was an easy fix. Keep in mind, if you open your phone, you loose your warranty.