Is it founded that those with respiratory disorders such as asthma are more susceptible to uri's and pneumonia?

Definitely: People with asthma are more prone to lower respiratory tract conditions such as pneumonia. Well-controlled asthma less likely to cause this.

Yes: It's very likely to be the case. The increased inflammation and irritation make you much more vulnerable to contracting viruses and bacterial infection than a person w/o the disease. Also, some of the medications you might take could lower resistance. Work w/ your doctor to find ways to strengthen or normalize your immune system. It's not easy - but diet/exercise/stress reduction can help. Best!