My husband and I have lived in our 100-year-old house for 2 years now. About 2 months ago we noticed "bubbling" of the paint in our bedroom near the ceiling, and found a roof leak which was repaired. Since that time, we've heard noises that sound like small falling objects between our bedroom wall and the outer wall. We initially figured it was due to the leak, but months later are still hearing it, and even in other parts of the house. Neither of us ever recall hearing these noises before. Is this normal with what we think are plaster walls? Should we have a contractor come look at it? We're not even sure what kind of contractor to ask to come out (general vs. plaster specialist).