I have smelly green mucus, cant breathe from right nostril what is this?

Sounds like you have some kind of infection. Possibly a sinus infection. Unknown if any type of drugs would cause this. Sounds like you need to see the doctor and you probably need antibiotics. Try buying some saline nasal spray and try rinsing your sinuses with the saline spray. That might help a little until you can see a doctor. Headaches are usually another symptom of a sinus infection but not sure what the neck pain could be coming from. Hope you feel better soon and please see a doctor!