Lungs
There is mucous and there is phlegm. Yours was phlegm from the lungs. Amoxicillin is a good thing to kill those little organisms in your lung that make your body produce those fuzz balls. Source(s): http://en.wikipedia.org/wiki/Phlegm http://en.wikipedia.org/wiki/Amoxicillin.  Even when you're healthy, your body is a mucus-making machine, churning out about 1 to 1.5 liters of the stuff every day. Most of that mucus trickles down your throat and you don't even notice it. 1 | 2 | 3 | 4. Continue reading below...  The other (more likely) location that the mucus may originate is nasal passages. If you are having a significant amount of nasal drainage that is draining to the back of your throat, then this may be where your mucus is coming from. The most common cause of this type of thing is season allergies. It can be temporary and occur as the result of a cold or flu, or it can become chronic. Smoking is a major cause of chronic bronchitis. Mucus in the lungs may be accompanied by a constant need to clear the throat, a persistent cough, wheezing, shortness of breath, chest tightness and fatigue, states the MayoClinic.com. You Might Also Like.  Your mouth, nose, throat, sinuses and lungs are lined with mucus membranes. These membranes contain mucus glands that produce--surprise--mucus. Mucus-producing membranes line specific passages in your body, like the respiratory and digestive tracts, for protection and support. The cilia transport the mucus layer toward your throat, where it could either get spit out or swallowed. Mucus defends your body. Mucus contains antibodies, enzymes, and proteins that work to help get rid of whatever's in the air you've inhaled that could make you sick. Clear phlegm or mucus from your throat by coughing or hocking. If an excess of mucus has made its home in your throat, it's okay to evict it by coughing it up. Find a remote place, such as a bathroom, and try to loosen the mucus from your throat by coughing or hacking. 2. Know if you may have post-nasal drip. Post-nasal drip is when your body produces excess mucus, and the mucus runs down your throat instead of out your nose. Post-nasal drip can be caused by colds and allergies, certain medications (including medicines for hypertension), deviated septa, and fumes from irritants. 1 In asthma, the passages in your throat and lungs become inflamed and produce excessive mucus. 2  Asthmatic responses can be due to allergies, occupation, or exercise (which could be exacerbated in cold, dry air). 3  Given what you have described, a third possibility could be cystic fibrosis. 4  Cystic fibrosis is genetic.  Mucus in the back of your throat can be coming from one of two different places. First, this mucus could be coming from your lungs. If you are a smoker or if you have severe allergies, you could be making a lot of mucus in your lungs that is then getting coughed up. If you don't find yourself coughing all that much throughout the day, then the mucus is probably not coming from your lungs. If you are having a significant amount of nasal drainage that is draining to the back of your throat, then this may be where your mucus is coming from. The most common cause of this type of thing is season allergies. Phlegm in the chest area can also appear. Most sinus infections are viral. Green mucus is usually thicker than yellow mucus, thus it tends to create sinus congestion, and sinus pressure. When that happens sinus pain, also called sinus headache, may also appear. 
https://answers.yahoo.com/question/index?qid=20131107152202AAGObCh http://www.webmd.com/allergies/features/the-truth-about-mucus https://www.zocdoc.com/answers/9942/why-do-i-have-mucous-in-the-back-of-my-throat-all-the-time http://www.livestrong.com/article/195795-what-are-the-causes-of-mucus-in-the-lungs/ http://www.mucinex.com/symptom-education/ http://www.wikihow.com/Clear-the-Throat-of-Mucus http://goaskalice.columbia.edu/answered-questions/mucus-buildup https://www.zocdoc.com/answers/9942/why-do-i-have-mucous-in-the-back-of-my-throat-all-the-time http://www.mysinustory.com/green.html
where does the mucus coming from lungs or throat?