It sounds like it could be one of two things:

allergies - you could be allergic to some sort of plant that most likely flowers all of the time (since you said you are in a tropical country)...

the other thing you can ask the ENT to check you for is chronic sinusitis - it's a bacterial infection that lives in your sinuses, and causes the greenish yellow mucus. It can be treated with antibiotics (make sure it is prescribed by a doctor).

One of the things that can potentially help you is to try to clean your sinuses. There are several ways to do this, one is with seawater, the other is with a thing called a Neti pot. It's like a teapot that points up - which is used to literally wash out the sinuses.

Good luck!

hey jahjah! one question, how is the supply of goods where you are, i mean, can you get pretty well everything? do you have any other symptoms regardless of whether you think they are relative or not? For example hows your weight, fatigue, head aches, cramps, sleep patterns, any allergies or diet issues. maybe if we have more to work with we could help more.

Hi danielv and timeisshort! Thanks for the replies.
I think that wasn't one question.
But I think, I am healthy.
weight - OK. No fatigues, head aches, cramps, sleep patterns, any allergies nor diet issues. I eat vegetables everyday. I love fruits.
So, I was wondering if it is really Chronic Sinusitis.. I've read about Sinusitis and the symptoms seem different..But possibly, I have Defective mucous membrane..
I am planning to see a doctor soon..and check out that antibiotics that might help me. But still, I was wondering if anyone has ever experienced this same case.

Hey jahjah, or any one else, I believe i can show you how to fix this & keep it under control, you will need to understand how and probably do some research to settle your own mind but i'm willing to help you through this. First i want you to google this; vital functions of salt in the body , there are 22 points if you like send me amessage by clicking my " behind the 8 ball picture" & i will guide you through how to do this successfully. i have used this for asthma cures, blood presure lowered to better than normal along with other things i am gaining help with.let me know & i will help you.
God Bless.

8. Salt is vital for clearing up catarrh and congestion of the sinuses.

I can't log-in..

bingo! now you need to learn how to use it. Its not about just using any salt, do you swim at the beach or is that not an option? Supermarket comercial salt is heat treated & stripped of the 84 minerals that are so important to our health so you need unrefined natural salt Sea salt or himalayan salt. Now did you know that your symptoms are a sign of dehydration? So you also have to make sure you hydrate properly so the guide lines are for every 20-25 kg ( or 40-50 pound) of body weight you should be consuming approx 1 litre of water per day. but don't try to do this straight up work your way up glass by glass if you have to but try to atleast have the same plus some each day, it takes the body approx 3 weeks to properly hydrate & the hard part is keeping it balanced, it takes our bodies some months to gain memory status & then we have to recognise the differenc between hunger & thirst Most time it's thirst.
Check out sole salt & well take the next step.
God bless!