I caught pneumonia in August 2001 (on my 25th bday!!) and was ill for literally 6 months due to repeated chest infections that followed the pneumonia. My asthma had gone mad as well. So yes, I think asthmatics are very prone to chest infections.
I also agree with the poster that said antibiotics are overused. The GP barely looks at you anymore...he just hands out the meds.
Take care and welcome to the boards!