Earache due to sinus pain, or 2 unrelated infections?

Earache: Earache is most often due to pressure in the eustachian tube as the normal ventilating air is reabsorbed due to obstruction and the tube collapses and generates a negative pressure (like suction) stretching the ear drum and sucking it inwards. This is uncomfortable. The same congestion that causes sinusitis can cause blockage of the eustachian tube so these conditions often go together.