What Causes Persistent Cough While On Protonix For GERD?

I ve been diagnosed with GERD. I rec d a prescription from the ER for Protonix I was doing nicely until around 2 PM today 48 hrs after my ER visit. I have a persistent cough and it productive with thin clear phlegm. Any advice for my recurrent symptoms? I v taken 2 protonix thus far and 1 chewable gas pill w/ calciun and symethicone. I need relief from bloating