I am a vocal student, but I lost my voice sometimes and my throat is not fully o

Question:

I am a vocal student, but I lost my voice sometimes and my throat is not fully opened. What should I do?

I have an allergy, but not very serious.

Additional Details

5 months ago
Sorry that I didn't tell you my personal information. I am 21 years old, female, classical music. I am Thai and I can't play piano. My teacher is Korean, he is a professional singer. I sometimes do well, but sometimes don't. Oh, I am a soprano, my range is between ...umm...I don't know what is the lowest one, but the hightest one I hit was (the next 2 cords)G sharp.

Best Answer - Chosen by Asker: 5 months ago
Sorry that I didn't tell you my personal information. I am 21 years old, female, classical music. I am Thai and I can't play piano. My teacher is Korean, he is a professional singer. I sometimes do well, but sometimes don't. Oh, I am a soprano, my range is between ...umm...I don't know what is the lowest one, but the hightest one I hit was (the next 2 cords)G sharp.