I am 15, I am a virgin, weigh 150 pounds or something like that, so I am a little overweight but so yeah, here's my problem, which is new. And I do not feel sick at all.

For awhile now I have been vomiting for seemingly no reason. Though, not extremely often, more then I ever had before. This never used to happen, in fact, I had gone YEARS without doing so in the first place. I know for sure I have some kind of acid reflex that I get throughout the day, but that's nothing new. But after never doing it, to recently, has been a big change. It started when, one time out of random I started coughing out this slimy clear stuff so hard I could see stars, this was after I had long john silvers for dinner... so if that could have had anything to do with it. I would NEVER do this on purpose. But also that wasn't the first, at one time I was eating chicken, and another for no reason whatsoever. I just woke up one night coughing. It always starts with coughing...
Is this some kind of strange food allergy, was all the food from these times bad? Since the other day my throat is oddly sore, and an older and not at all new thing is a tightness in my chest when I tense up or move in certain ways. Also, with the slimy clear liquid like stuff I was coughing up, is that normal, that, and seeing little sparkles, floating around.. . Sorry if I sound like an idiot, just a question... and, oh sorry if this is in the wrong section.

Seeing stars is normal for intense coughing, feeling faint or dizzy, getting up suddenly.
Slimy stuff when you cough is normal too.
What isn't normal is chronic vomiting. It might be related to your acid reflux (not reflex). If your esophagus isn't closing normally after food empties into your stomach, acid backs up, burns (your stomach lining is magic, the only organ that can tolerate the acid), and food backs up too, and you might vomit. I chew Tums practically all day long for this, which you don't want to do, because too much isn't good for you. There are many other anti-acids on the market, and prescription ones too. Don't eat for the few hours before lying down, avoid spicy foods and caffeine, etc. Perhaps you know this already.
But there are plenty of other conditions that can cause vomiting, from ulcer to appendicitis to gall bladder problems, and more, so see a doctor.