annual unusual coughs after a cold heals

[alihares99]

I seem to have a condition for about 6 years and no doctor can actually diagnose is correctly. at around spring, summer or sometimes fall, I usually catch a cold. but that's not the problem. that's just where the problem begins. after the cold completely heals, I start to cough for about a month without any signs of cold or virus or bacterial infections, where by cough I mean really strong ones that even can cause me to vomit. After about a month, coughs just wear off with no sign at all. I kind of feel that some sort of liquid like mucus is always running in my throat all the way from my nose to my stomach. I can actually take out this liquid from my nose, which I don't exactly know its name, and it gives me a feeling of relief. it seems like it was stuck there for a long time, running slowly down to my throat. Although I have this feeling all year round, but only after a cold does it cause coughs. Even when I vomit, it is this mucus-like liquid that comes out of my mouth, if my stomach is empty. For the record, It is very thick and colorless. I have been diagnosed with vast variety of diseases from asthma to allergies, but the coughs didn't ever respond to any treatment even a bit. I am losing my hope that any doctor can diagnose what it is and have it cured. I really could appreciate a helpful reply. Thanks in advance.