A pepper mill is read as spice and provocation — the wish to add some heat to something bland. Grinding it can stand for patience in wearing a problem down.
Does the traditional reading fit your dream, or did it mean something else to you?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.