What Causes Difficulty In Breathing With Pain Around Back And Chest?

I am having difficulty breathing (not getting a satisfying breath that is) not all the time but sometimes. I had a doctor give me clonopin for anxiety once before but this time it is accompanied by headache and different aches and pains around my back and chest areas. thinking those pains might be from breathing deep on occasion. the headache is concerning cause it has been one and a half weeks. going to doctor tomorrow. what tests should be run and what is you opinion