Bad smell from mouth. From 10 years.

I went to dental because I am having bad breath problem whole day from last 8 years. This bad breath is also there after brushing. Dr. Did scaling & polishing and gave me a mouthwash (chlorhexidine gluconate solution) but it didn't worked .I am still having bad breath. One of the dentist suggested me to go for ENT. When I wake up in the morning my mouth smells very very bad, than after brushing also my mouth start smelling after few min, brushing 2 times a day don't make any effect on my bad breath. My friends say you have unusual smell in your mouth because of which I am not able to talk with anyone. This unpleasant smell is not for sometime ,its whole day. Do not know why. Please help me. Note- x-ray paranasal sinuses is done and ent specialist said everything is OK. I am attaching the prescription which was given me by ent specialist but the medicines didnt worked for my bad breath and i am still having that same bad breath from 10 years ...