The tightness in the throat/chest can be caused by the Advair. Not everyone can use it. I've tried both Advair and Serevant and had to stop both because they irritated my throat and caused such tightness in my chest that it was worse than the asthma. I got so hoarse with the Serevant that I could hardly talk. A day or 2 after stopping it - I was ok again. I now take Asmanex instead.
For the leg cramps - it could very well be the potassium loss caused by the prednisone. My docs used to tell me to eat a banana every day when on the prednisone or drink OJ and eat yogurt. All have potassium in them.
Hope you feel better soon!