How old are you? Have you eaten a lot of meat or other fatty foods in your life?
What kind of vitamins, herbs, and/or mineral supplements do you take? Have you done the entire Cure Zone recommended Cleansing Protocol yet? Have ever fasted on distilled water only for a few days?
There are so many things that it could be, and no way for anybody to know for sure what it is. The best thing you can do for your body is the Cure Zone Cleansing protocol plus make sure you are getting plenty of Iodine with companion nutrients. Most problems will clear up on their own if you do this. There may be a few things that require a distilled Water Fast to resolve.