The following is a q and a session from Myasthma central.com I though my fellow asthmatics might be interested in:
Your question: I have an itchy sensation in my upper back and chest. It feels like my lungs are itching yet I can't scratch it. Does this have something to do with asthma. I used to get this sensation a lot as a kid, yet accassionally as an adult. I just got over a week long dose of antibiotics for an infection that I think is resolved by now. What do you think?
My humble answer: I'd like to reiterate this could be normal with asthma. It could be that the infection in your lungs is breaking up and the secretions in there are irritating your airways, causing them to itch. I had this feeling many times too, although mostly as a kid. I think it's more common in kids because their airways are smaller (this is also why asthma tends to be worse in kids too).
It usually resolves with time, or sometimes with the use of your rescue medicine. However, if it doesn't, it might possibly be an early warning sign of an asthma attack, perhaps caused by a new onset of infection. So if it doesn't dissipate you may need to put your asthma action plan into action.