Non-stop Coughing spasms

I don't know if this is what it would be called, but I often have trouble with coughing spasms. I will cough and cough and cough and can't stop to catch my breathe. It is not a deep cough that coughs anything up, it is just like a tickle that won't stop. It sucks every bit of energy out of me and can last hours at a time. If I am able to get some regular breaths I can sometimes stop it for short periods. I wish I could describe it better. I am wondering if this happens to anyone else and if you have a treatment that works for you. I have spent the last week sleeping upright in a chair--as much as I can. Also doing my Duoneb treatments helps while I am doing them, but the effects don't last. I am probably doing 10-12 nebulizer treatments a day. I am feeling really down and I don't know how long I can go on like this. I am taking 50 mg Prednisone and an antibiotic--but hasn't made a difference. I sure would love to hear your thoughts on this. Thanks!