What Causes Coughing And Strong Smell In Nostrils Along With Breathlessness?

i went to a training one day for three weeks. Each time i began coughing out of control, felt like i couldn t breath, and the smell of cigarettes were in my nostrils. The very last time i went was two weeks ago,and i still smell cigarette smoke all day, every day. I went to the doctors a week ago, and my doctor put me on antibiotics and steroids. I also had a MRI and everything came out fine. i don t know what it could be. it is very strong, and my nose really burns. What could i do to get rid of this smell?