Wheezing probably isn't a lithium thing. As we age, our allergies change. I learned that when I developed some really severe allergic reactions as an adult that never were an issue as a child. An allergist explained that it wasn't unusual really at all. In my case, it was actually the hormonal changes in my first pregnancy that set my allergies in motion believe it or not. It can be changes in location, dietary changes, exposure to chemicals/mold, etc. (often you don't even realize you are being exposed to them, like the mold issue that developed in a few rooms in my school building at one time). Whatever the case, see your family physician about the wheezing to be assessed in case you need to have medications on hand in case of a severe reaction.