Question about Losing Upper Range

Hi, I came across your website and thought you could help. I've been a high first soprano since my sophmore year of highschool (I'm a junior now). When I first entered highschool, I could not sing high notes at all, but then started my upper range started to develop [and a bit of my whistle register too]. I switched to a different voice teacher in the middle of my sophmore year and thought I was making progress with her. She focuses a lot of her training on strengthening the muscles of the face [by making her students make strange stretched out faces while singing] and uses lip trills and excercises that place the sound in the nose for warm ups [like "nay nay nay"'s and "ng" sounds]. I almost never actually sing when I warm up with her. It's generally just lip trills, "nay nay nay"s, and "ng". I seemed to be doing well with her lessons, and thought her training was helping. However, when I entered my junior year, it started to become difficult to sing higher notes. [I also continously had throat health issues; during my sophmore year, i started to get very bad sore throats, to the point where sometimes I would not be able to speak. these would linger for a few months]. I began to crack on notes that usually were not high for me [such as a G]. I'm near the end of my junior year and the problem has still not been solved. Now when I sing, my upper range just sounds weak and hoarse, when it use to sound full and strong. I use to be able to sing High Bb's, but now I can barely reach it without cracking. I don't know what's wrong  I went to my doctor numerous times and he said it was probably allergies that were causing my throat to be sore. However, I've taken the allergy medicine and it has not helped. I'm not sure what is wrong with my voice, I feel like I'm losing my upper range, please help! 
===============================================

Thanks for writing me with your question.  I'm sorry to hear that you are having such difficulties. I should start by saying that I can't be certain about what's going on with your voice without hearing an example. But a few possibilities come to mind.

The exercises you mention may be fine or not depending on how you are doing them. Based on the problems you are having I suspect that you have gotten in the habit of doing them in an unproductive way. Stretching is good, but if you stretch in a way the eliminates a good resonating form you will have trouble. (An example of this would be stretching the front of the mouth or just the face and not including a stretch of the back of the mouth.) This is because the throat space will close, which includes a raising of the position of the larynx. When this condition exists it often leads to sore throats because the tissue of the throat gets irritated. The inflamed tissue leads people to wrongly assume that allergies are to blame.

The closing of the resonance space and the higher larynx position would also make sense with the difficulty and cracking in the higher range. The extension of the range is dependent on the stability of the larynx so the vocal folds can stretch for the higher pitch. If the larynx is allowed to rise it will not allow the folds inside to stretch for pitch. The high range also depends on the stable larynx to keep the resonator of the pharynx open. The proper resonance reinforces the vibration and amplifies the tone so the vocal folds can vibrate smaller in order to vibrate faster for higher pitch. When this is lacking the voice gives out or strains in order to produce higher pitches.

Like I said, I can only give educated guesses based on your descriptions. If you want more accurate feedback you are welcome to send me a recording. It can be some exercises or a song. But if you can show me some examples of the difficulty I can give you a more accurate assessment.