I have been preaching now for over 20 years. From my very first sermon even until now, each time I preach at some point I'm going to experience a tickle in my throat. I have learned over the years to manage. Sometimes I preach with a cough drop tucked between my cheek and gum. But by the grace of God we do what we're called to do through our weakness. I'm glad His strength is made perfect through our weaknesses.
Herschel Hobbs had some voice problems once and wound up going to a doctor. The doctor told him to keep raw peanuts in his pocket and eat them often and they would coat his throat. He took that advice and felt like it was the best advice he ever got. Maybe this will help someone.