Grinding grain or coffee is read as slow, wearing work that turns hard material into something usable. Dream books also link it to the daily grind and to tension held in the jaw.
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.