Can any singers/singing teachers explain?

My advice is think low and find a focal point to sing to(this is what call spinning the sound) and keep pushing the diaphragm down and free up the throat, and keep the throat open(open throat) . The key thing when singing up in high registers is this, support comes from the diapraghm and also lift (which means lighten the sound and at the same time support it and sing to a focal point and keep the sound "pushed" down , open the throat, but do not let it go to the chest voice. Also, I tell my students to think of a narrow space or create a narrow space with their hands and sing within the narrow path and this way it'll help you push the diaphragm down more and plus the sound will be more focuse and it's okay if the sound is small. It takes awhile for small sounds in the higher registers to get bigger. My advice also is when you hit middle E, start to lift, in the middle range, chest voice is fine when you go from C3-D4 and you can sing on head voice as well and its to start to change the higher you go. I would practice "lifting" from E4 to the highest note and build it up from there. You are a soprano range and I think you can go above your range. The most important thing is to grasp the head voice very well and also find the lowest tone you can sing to. In order for you to go to the highest tone, you have to find the lowest tones. In my teaching, I work in the different ranges to strengthen the voice and I also do that to make the "connection" a little bit easier and more smoother. I work in the middle first because that's where it's tricky, and once that is in place, I go for the lowest, and I go to highest and it's become effective according to my students. I think'll you'll reach it past the octaves you are now. In singing higher, you will have to take a really good deep breathe from the diapraghm, and you have to engage it and give energy and when you feel light headed, stop for a few minutes, this is normal, it just means you are taking in more air and it's normal. The key thing is practicing and find a focal point to sing to and relax and when you sing high drop the jaw and it's okay to stick out the tongue. If you have any questions you can e-mail me:mamurick@rockhurst.edu