I have read your question,
You have not mentioned the frequency of the cough .Cough since 6 years could be a serious issue , If you are experiencing chronic cough
, breathlessness , weight loss
, evening raise of body temperature, loss of appetite ,it could be chronic allergic bronchitis
.I think we can rule out sinus problem since just filling of water is not enough to conclude sinusitis , it is generally accompanied with headache , nausea and swelling at the affected area.
Tooth decay is not related to cough and requires a dental attention, water eye could be due to infection of lacrimal gland
, it requires consultation with an ophthalmologist.
For cough I would suggest you to consult a chest physician immediately.
Wishing you a good health,