I get this bitter metalic taste on my upper palate. i thought it could be the vitamin d and omega 3 supplements but even when i stop taking these for a week i still get it. its better when i exercise/run and worse when i dont run.

Metallic taste: Metallic taste could be due to medications, including OTC's & supplements, GERD, neurologic impairment, electrolyte imbalance, gum disease, with most common cause is bleeding from infected gums. Start with a dental examination and professional cleaning. If gum disease is ruled out, then see your General Physician to pursue other avenues of investigation.