Mine was seemingly related to my acid-reflux. Now that Obamacare has forced my insurance to no longer cover my inhaler, I really do suffer with it. The powder based inhalers do not work for me due to the way my throat is constructed - too large of a uvula for the powder to pass.
Try asking your doctor for “Albuterol”. It’s not as popular these days, I suspect because it’s generic, and therefore no longer big $$$ to the pharmaceutical industry.