Bronchitis!!!!! tell me!?

so the other day i my chest hurt so bad and i got lightheaded and i felt i couldnt get enough air; so i went to the hospital and they told me i had a little bronchitis in my lungs. the thing is i dont have a cough but my chest hurts so bad and when i go outside walking or anything where i move alot i start to feel i cant breathe and i start to paic and feel im about to have a heart attack. the doctor said my heart and cardiac and all that was okay but i feel like im gonna die. im just asking because i want to know how long this is gonna last. i couldnt go to school becasue i felt like someone grabbed my lung and squeezed it i just know know what you think... doctor says i have bron chitis i have no cough i feel i cant get air i feel like im gonna faint (or die) and i my chest hurts really bad... is it bronchitis or is the doctor a dumb?