1) The top of the head has lots of nerve meridians that hook up to many points so it has been added recently. You can use it if you choose too. I get great results just using the first 7 points.
2) The sore spot is tough for some folks to find. If you go slowly and firmly from the middle of your chest outward you should find a spot that will feel more sensitive than any other area on your chest because it is a lymphatic drainage point. If you can't find it the karate chop point works fine for most people.
3) I suggest you make a movie in your head of the last time you were in a plane and/or doing public speaking. Try to make it as vivid as possible and get your intensity level up. If you can't do that then maybe you can do it right before you are in that situation. Many people tap when they are on the plane or right before a public speaking engagement. I had to do a radio show recently and was panicking about it the night before. I tapped on the way to the station and while I was at the station. Everyone told me I sounded smooth as butter on the radio. The EFT really helped me to deliver. You may find that if you tap anyway and say a setup phrase like "Even though I can't feel any emotion/feeling about this memory ...(plane trip/speaking) I deeply and completely accept myself". Some of us are better than others at blocking out painful memories by dissociation or other means. But believe me it's in there somewhere. I call them "gushers" like when you strike oil. This happened to me recently with some chest pain I was having. I couldn't connect it with an emotion but knew there was something there. As I tapped I realized it came from my wife dumping a huge emotional load on me the day before. I helped her tap through her many issues the day before and just forgot how heavy it was. But it came up as I was tapping and it was my own "gusher". That's how it works for those of us not in touch with our emotions. Keep tapping and it will pop up. That's how EFT seems to work.