Re: Brushing/flossing Too much?
Can't really tell if there's such thing as brushing too much, but I can tell you that you don't have to over do it. 2-3 times a day is enough, in fact I believe that that's what most dentists recommend. Once in the morning, maybe during the day, and at night.
I'd be more worried about what you eat, and when, so cutting down on the sugary stuff is a good thing for sure and I wouldn't go back to 2 liters of coke per day, that won't get rid of your tooth ache.
Perhaps some of your cavities are causing the soreness?