Recurring severe sore throat

Hi all.
Every month I have a very severe sore throat.
I've tested a throat culture for Strep. A and it came back Negative.
It usually takes 10 days for my throat to get well, during wich I can BARELY SPEAK !!!
Sometimes during those 10 days I begin to cough with green mocus.

My recurring severe sore throat happens when one or some of the fallowing happens:
1) I speak loudly for 25 minutes.
2) I breath cold air at night when asleep ( Through nose ).
3) Don't dress properly when chilly outside.
4) Eat roasted watermelon seeds and then speak for few minutes
5) When someone infects me ( They are sick for 2 days, I get sick for 10 days !!! WHY ??)

I try gargling solt water, but it barely helps.
Should I consider removing my tonsils ??

Those repeated sore throat MESS UP MY PROMOTION IN THE COMPANY!!!
The bosses are afraid to make me team leader cause I can't speak for 10 days every month!!!
Please!!!!! Any Ideas ???