HI, I am male Ali 22 years old from China, I am suffering from constipation problem from one year, I have seen the doctor many times and have done, many tests, Thyroid function tests ,CBC, Gastroscopy, colonoscopy， another test for Assessment of food movement may demonstrate a prolonged and delayed transit time, liver function test , ..etc,I also do not have diabetes mellitus , all my tests are ok, the doctor said all tests are clear, But i still have the problem, every time i go to hospital to see a doctor he give me some medicines but no use, always i went to toilet, i feel sensation of incomplete bowel evacuation, so less stool, not hard not so soft but thin and less nearly light black color, during constipation i feel sputum in my throat, and sometimes i felt soreness in abdomen and throat, all the time i feel like burning in my abdomen and bloating , while sleeping i often feel bloating under the xiphoid process , i drink a lot of water everyday but still my skin is dry and now i also have pimples at my face, please tell me what problem i have and what should i do to get rid of constipation