I was diagnosed with RAD and put on pulmicort for some of the same symptons that you have. Then, took the MC test and came out positive and was diagnosed as asthma. Then, began taking Nexium and haven't had a single episode of tightness of chest, coughing, or anything that I used to have just a few months ago.

Now, it's back to RAD. My RAD is caused from acid reflux. I have another post about it - please see it also.

I also took Advair 50/500 and had a Maxair and albuterol inhaler for the rescue inhalers. Took the maxair one day after an aerobics class at the gym and thought I was going to die it burned my throat so badly. Come to find out, it wasn't the maxair after all burning my throat, it was ACID! I had jumped around so much in the gym that I literally made my stomach push the acid up to my throat.

Hope this helps you some and good luck! Talk to you doctor to see if he/she can find the reason behind the RAD. It could be many different things, so it's important to figure it out soon so you can get some relief. I know exactly how you are feeling. I've been there and it's not fun!