I really want to find help on my teeth. i wouldve like you to judge if where i have dark brown decay is stain or tooth decay. if decay i need to fill it, in case stain no? what do you think?

You'll need to see a local dentist who can examine your teeth and determine if you need a thorough cleaning or restorations. Very difficult to do this over the internet and far beyond the scope of this website.

If you drink lot's of coffee or tea or smoke and chew tobacco than possible stains. If you have poor oral hygiene habits and eat a lot of sugary foods, than decay. Either way you must see a dentist for exam and treatment if you want to keep your teeth.