Could be asthma (perhaps a mild form) - could be your allergies causing it - perhaps they are worse this year (mine sure seem to be) - could also be Reflux/GERD.
Both asthma and reflux seem to be worse at night - and can cause a cough. I think your best bet is to write down all your symptoms and go see your Dr. to get some testing done - so you can get treated and get some relief.
I have asthma, GERD, allergies, and high blood pressure - what a lovely combo
- Any one of my conditions can adversely effect another so it is important to find out what is going on - even if its a combo - and get treated for each.
Take care of yourself - and I hope that you feel better soon.