Please i don't no what is wrong with me, am always having catarh every night the moment i lied down to sleep. i have taken different drugs but no change. I don't take cold water, i dnt use the fan or AC, but its still constant, please what is d cause of these frequent catarh and the possible solutions to it

a runny nose might be an allergic reaction sometimes...

Firstly Since you are saying that you get it mostly when you lie down to sleep, it may be that your bed (or room) is so dusty or it smells in a way that triggers this reaction....

Secondly It may be due to cold, (you don't have to be shivering first before you know you have a cold, as it may be mild) meaning you don't have to buy drugs You just read this here how to clear your nose...
http://www.newsphases.com/2016/02/blocked-nose-how-to-clear-it-up-without.html

If that doesn't work then, aboniki or robb will suffice, remember what I said firstly, (because that may be the reason why those drugs did not work)

Stay Healthy, Stay Wise