I'm 20 years old and suffering from bad breath for about 4 years .i don't have plaque and cavity. I brush and flossing my teeth everything. I also use a tongue scrapper. My overall digestive system are fully okay because I tested it about 4 months ago. I smelt very bad even after brushing. I gargle with salt water everyday but I can't solve this problem. After eating any food my mouth smells extremely bad and metallic taste coming from my mouth. Please help me!