Does a dead tooth root mean you have an infection. also can it cause pain weather it is infected or not? can it cause a ear infection or ear pain?

Dead tooth: There are both sterile and infected necrotic pulpal involvements. Both can permit spread of toxins and/or bacteria. If it's a lower back tooth, there may be ear-area involvement. You need professional care, NOW. The longer you wait, the greater the risk of complication, the more extensive (andexpensive) the damage control. Please seek immediate dental care.