I Have Had A Cough For Over 4 Months. I

I have had a cough for over 4 months. I have been on multiple antibiotics, steroids and inhalers with no relief. I have had sinus CT scans, chest x-rays all negative. I tested negative for pertussis and TB. Also be on acid reflux medicine which didn't help. The doctors are stumped. Any suggestions. I am worn out from coughing.