Each insurance company has its own criteria for whether or not a given procedure, such as a breast reduction, will be "covered." At 5' 6" and 200 pounds, even with a bra size of 44DDD, my guess is that this will not be covered. The company would be more likely to insist on weight loss or, at least, multiple documented attempts of conservative therapy, before agreeing to provide coverage. That is just my guess, though.
The next issue, as always, is finding a board-certified plastic surgeon who participates in your insurance and/or is willing to accept what the insurance offers as "coverage" as payment for the surgery. That has become increasingly challenging over the past few years.
The first step is to find a surgeon you're comfortable with and to try to obtain approval for the surgery. I think it will be difficult based on what you say, but, as I indicated, each insurance policy has its own criteria.
I hope that this helps, and good luck,
Dr. E