Hello,
Gastritis, fluctuation in estrogen levels, heartburn, postnasal drip, dental caries, tooth
abscess are few other causes of metallic taste
in mouth. Intake of medications like metronidazole, blood pressure medications, and thyroid medications all can lead to this symptom apart from the causes mentioned by you. The associated symptoms may help in arriving at a diagnosis. Seek medical help.
Take care and regards!