Suggest Remedy For Chest Tightness And Difficulty Breathing

Today I had a bubble echocardiogram. Shortly after the test my chest felt tight and it was hard to breathe. That went away eventually but tonight my chest is tight again on my breastbone area. I have a very sensitive breastbone area and have had problems before with an echo (without bubble) especially if they hold the monitor in one place too long...possibly something to do with the vagus nerve?? I just feel bad in general tonight, very tired and the pressure on the breastbone area...no pain however. Could it just be irritation from the test.....I even have trouble with that area of my chest hurting at concerts when the speakers are too loud and vibrating. The test did show a very small leakage of saline but the doctor just told me to take an aspirin a day.