I am a 37yr old female smoker. i cough chronically more so at night while laying down. sometimes i cough up mucus that is either clear, green brown.

Quit: The best answer is "quit." you are developing chronic bronchitis and possibly emphysema. That is never a good thing.

Cough: If you have a cough with sputum production then you have bronchitis-possibly chronic obstructive bronchitis (COPD) given smoking history. Cough however is often multifactorial and can be worse at night due to gerd/reflux or post nasal drip or aspiration or even irritant exposure (such as from sleeping on down pillows/sleeping with pets/etc) to name a few.