How Can persistent Cough Along With Wheezing Be Treated?

I am very rarely sick and only had a cold a handful of times in my life. I have had the flue a few times that lasts one week. Over the past year I have had a sciatic nerve issue. But now over the last three months, I have had constant periodic cough and at times, I cough up thick phlegm or it gets lodged in my throat that almost strangles me. I have taken Muscinex and it does not work. At night. it sounds like I am wheezing but it is not coming from my throat. It seems like it is coming from my chest. I am breathing fine. Because of my sciatic nerve on my right side, I sleep on my left side--this is when the noise in my chest wakes me or my gentleman friend when we are together. When I lay periodically on my right side or back the sound from my chest goes away or subsides.