What could be causing my chronic earache and facial pain?

Evaluation Needed. The symptoms you have mentioned can from a myriad of pathology's so go to your doctor to be evaluated.
Facial pain. 5th nerve branches. Earache is possible mastoid infection or ear infection or temporal bone lesion. See an ENT person. They will have to look in your ear and also do MRI imaging. I suggest ct imaging of the temporal bone also as felt necessary by the specialist.
See OFP specialist. Orofacial Pain specialists are dedicated exclusively to the treatment of orofacial pain, TMJ pain, jaw pain, facial pain, bruxism and TMJ disorders. Find a doctor close to where you live or work.
Trigeminal Neuralgia. Tn is a specific name to a type of facial pain. It can take a few doctors visits to get a final ruling. Don't wait it is not cancer but the pain can make you wish you were dead! think flesh/tissue and not nerves for face pain! begin a self-care wellness program of vits, magnesium, sleep, self/pro massage, chiropractor, heat, stretching. I use acupuncture and trigger point shots! see other answers.
TMJ. Strong chance of a TMJ problem. See oral surgeon for evaluation and diagnosis. If TMJ, see TMJ expert. Any dentist can be a TMJ expert with the proper training and experience. Most commonly, oral surgeons, prosthodontists, and orofacial pain specialists. Ask your MD, your dentist and your dental society for referrals.