Diet is very important to health. If you are extremely over weight it can lead to problems such as fatty liver disease, which can damage the liver.
It is a serious sign to have tea colored urine.
This article explains some of the health risks of obesity: http://www.webmd.com/cholesterol-management/obesity-health-risks
There are things you can do that are easier than you realize. Changing the quality of the food you eat, eating 5 smaller meals, rather than 3 will help speed up your metabolism. Work up to walking an hour every day (don't start all at once - start by walking only as much as you can tolerate - but do this daily - since you are showing some health problems get directions from your doctor). Simply increasing your metabolism in these ways will help to control your appetite, plus help you to use more energy even when you are not exercising.
It is important to understand that some types of foods cause inflammation in the body which can lead to the liver problems and other problems. A good source on what types of foods to eat and what foods to avoid can be found here:
Trouble sleeping can be related to sleep apnea caused by the enlarged throat. Please sleep with the head of your bed up until you can lose weight or be evaluated. Having difficulty sleeping will only increase the weight gain, because sleep is needed for the body to process stress, etc. Increased stress hormones also cause an increase in weight. See: http://helpguide.org/mental/stress_signs.htm
The 3 web sites I sent you are great references and if you do nothing but study them, you will begin to see that there is something that you can learn about each day that will help you. Just take it one day at a time, but do something each day, as this is serious. You are young though, so the ability of your body to respond to changes is very good.
If you have not seen a doctor about the tea colored urine and chest discomfort, please do this as soon as possible so that andy acute problems can be treated.
I hope you will find this helpful.