I have broncho spasm and i heard that smoking marijuana can expand your airways for better breathing? could this be true?

Not long-term: There was one study that showed short-term marijuana use could be associated with some bronchodilation, but that long-tern use produced symptoms of obstructive lung disease (sputum production, cough, difficulty catching breath, etc). So it seems that ultimately, marijuana can irritate your lungs just as effectively as regular cigarettes. Plus, its smoke contains more carcinogens.