Hi there!
Well, without a clinical evaluation it would be difficult to specifically determine the cause of your symptoms. Bitter taste could result from infections, inflammations, micronutrient deficiency, medication/ drug/ food item side effect, radiation exposure, hormonal/ endocrine issues, heavy metal poisoning etc. With associated sore jaw this is likely to be infectious/ inflammatory in nature. If there are no other symptoms, you could try taking multi-vitamin supplements for 3-4 weeks. If the symptoms do not improve or aggravate it is advised to consult a primary care physician for appropriate management.
Hope this is helpful.
Take care!
why have i got bitter tatse on my lips