Frustrated

I constantly have a cold and some phlegm... almost! It's only in summers that I am able to use my voice as I please. My throat feels so rigid and mute the rest of the time! I am frustrated! Anyone got any ideas? I try to keep away from having salads and try to have only warm food but I just have this constant problem! I just lack the unrestrained (musical) expressiveness and feel so handicapped! :-(