Are you ears going to hurt more swimming twelve feet down in your swimming pool or twelve feet down in the middle of Lake Superior?

It depends on the altitude of your swimming pool. The ambient pressure will be relatively close at only 12 ft. no mater the altitude. If you were to ask whether it would hurt more at 30 ft. in a pool or in Lake Superior, then the altitude will be more of a factor. Lake Superior is appx 600 ft. above sea level, therefore, the baraometric pressure will be different than a pool at 15,000 feet above sea-level. In this senario, your ears would hurt more at 30 ft in Lake Superior than in a swimming pool at 30 feet. This is of course all assuming that by using the term "Ears Hurt" you mean where would they have more pressure, because as your ears equalize, they shuld feel the same at 12 feet underwater as 100 feet. tritonunderwater.com