i'd be careful with cayenne. i used to use cayenne pepper to bring my voice back when i needed to sing at a show and my voice wasn't strong. and guess what - as a result, i now have scar tissue on my vocal chords. what worked pretty well for me was throat disks, and slippery elm lozenges aren't bad, either.

your sore throat could be caused by overuse, irritation or infection. infection should be dealt with by a doctor if it doesn't go away.