Hello dear user! I have gone through your query and understood your concerns! Thank you for sharing them on healthcaremagic. Severe cough is found in to many diseases of the upper and lower respiratory tract. It may be dry cough (without phlegm), or productive cough (with phlegm or sputum). Since you are a weed smoker, the possibility of acute bronchitis is very high. Smoking also worsen chronic bronchitis too. Larynx inflammation is possible during smoking too. Dry cough is found also in many malign diseases of the airways or lungs. So to determine the real cause of your cough you would be better do some routine test and a doctor consultation. An auscultation of your lungs must be performed to rule out bronchitis. A simple chest X-ray would be worth too. Your doctor may ask you for further examinations if he sees it necessary. HIV is not likely the cause of these symptoms. You have resulted negative in your test, anyway during first three months there are chances for false negative results. Perform another test some months later. I hope this answer was helpful to you! Please kindly rate it as helpful and write a short review about your experience with me! I would appreciate that a lot. Thank you and best regards! DR ERIOL.