Excessive mucus and coughing and gagging all night, I am COPD patient

I have copd so i am told and I am a mouth breather i have seen three doctors over three years. I wake up during the night all mucased up coughing and gaging like a cup full. The Doctors got me on 5 different puffers & every antibiotic & predizone too much there is. Over the last 1- 1/2 years Its usally mostlclear flem somtimes got green in it.Chest x-rays have been done.They say its namonia &broncile infection. I smoked for 45 years and quit a 1-1/2 years ago. Can you please help as can hardly breth some times and can not do anything with out running out of breth