Sinus drainage or an upper respiratory infection such as bronchitis or pneumonia. See a doctor if the coughing has persisted for more than a few days, especially if you feel poorly and are running a fever. Hope you feel better.
Having an uncontrollable cough is a medical condition, and I would suggest you seek medical advice. Pertussis is a highly and contagious disease, that can cause not only uncontrollable cough, but also a violent one.