Welcome to the forum!
So dental causes are ruled out in your case, except maybe an artificial filling or denture if you have. So let us look at other causes. It could also be an abnormal perception of bitter taste called dysgeusia. GERD and heart burn too cause metallic taste in mouth. Post nasal drip as in sinusitis, salivary glands infection,pharyngitis or strep infection too are common causes. Sjogren’s syndrome and copper or lead toxicity are other possibilities. It is also possible that you have diabetes. Sjogren’s syndrome too can cause decrease saliva, decrease sweat—this could cause the burning sensation.
Hope this helps. It is difficult to comment beyond this at this stage. Please let me know if there is any thing else and do keep me posted. Take care!
Thank you for your suggestions. I think the taste is in my saliva as I notice when and after I eat or drink, but not so much inbetween times.
Thank you for your suggestions. pins and needles in my fingers and a funny 'burning sensation in the palm of my right hand yesterday. No heart burn, and sinuses feel clear, but I recently had a permanent bridge put in and other dental work. Gums are fine and no fillings falling to pieces that I can feel.
Thank you, Sally