Hello, I can understand your concern. It seems that the tooth that was treated by root canal years ago has got re-infection or an adjacent tooth might be infected. Toothpain can be referred to ear and other jaw as referred pain. The infection of the infected teeth can be relieved temporarily by antibiotics and painkillers. However, some mode of treatment is always necessary to permanently eliminate the infection. Thus, you may have to go for re-root canal treatment of the tooth after removal of the cap (crown) or you can get the tooth extracted depending on the clinical judgement of the dentist. Infected tooth can cause fever as with any focus on infection in the body. However, chills are not associated with tooth infection. As you have taken just one antibiotic so far, you may need to wait for 2-3 days till the action of the medicines start. Till then, you can take Ibuprofen 400 mg or Ketorolac 10 mg up to three times a day for relief in pain. If the fever and chills are not cured in 2-3 days, then you should consult a physician as they are not due to tooth infection. I hope this information helps you. Thank you for choosing HealthcareMagic. I wish you feel better soon. Best, Dr. Viraj Shah