Hello Akash. I've been on a variety of Egoscue exercises, they change the set every couple of weeks when I visit them. By now, I don't think there's one "magic" exercise that will fix things.

To me, the pain spiking when looking down means that the position of the neck being bent forward is trapping nerves or placing more strain on muscles that weren't designed for them. In general, the head is pretty heavy and is meant to rest on the spine and thereby the legs. Pulling the head forward is now asking several neck and chest muscles to support the head. This is ok on a temporary basis but if we have a long term habit of doing this, nerves, muscles etc are taxed/irritated and will react quickly to even a few minutes of looking down. This is my understanding, anyway.