I am 24, 5'3 & weight 140 lbs, I am a 34DDD, waist line at 28in, would I be a proper candidate for breast reduction?

That's all I need to say! You are most likely,suffering from back, shoulder and neck discomfort. Which will be immediately and permanently improved with a eduction. You also get an tremendous aesthetic improvement as well!

Thank you for the question. Based on your description of cup size, you may be an excellent candidate for breast reduction surgery at some point. “Official” recommendations of course would necessitate in-person consultation.
Breast reduction surgery is one of the most patient pleasing operations we perform. By removing “excess” breast tissue, adipose tissue, and breast skin this operation reduces and lifts the breasts to a higher position on the chest wall. When a breast reduction is performed, a breast “lift” occurs as part of the procedure. Patients often find improvement in neck, back, and shoulder discomfort and find it easier to form their activities of daily living and exercise.
Timing of the operation will depend on the patient's life circumstances. In general, it is best to do this procedure ( like all other elective body contouring the stages, when patients have reached their long-term stable weights ( as you are doing). In doing so, there is an "improvement" in the safety of the procedure and the need for further surgery ( in the event of weight gain/loss after the breast reduction procedure) is minimized. Breasts may change, unpredictably, after pregnancy. Often, changes seen with pregnancy include a decrease in size and/or change in position.
Sometimes breast reduction surgery is covered through health insurance. The best way to obtain insurance coverage for breast reduction surgery involves some “hoops” to jump through. The more documentation you have (for example, from your primary care doctor, physical therapist, chiropractor etc.) the better when it comes to obtaining insurance “authorization” for the procedure. This documentation and letter/pictures from your plastic surgeon will help you obtain authorization.
When the time is right, seek consultation with well-trained/experienced board-certified plastic surgeons. Ask to see lots of examples of their work and communicate your goals clearly. I suggest that you do not communicate your goals in terms of achieving a specific cup size. For example, a “C cup” may mean different things to different people and therefore may be a source of miscommunication. In my practice, I ask patients to communicate their goals with the help of goal photographs.I hope this, and the attached link, helps. Best wishes as you work towards your goals.

Very hard to say if you are a candidate without a formal exam by a Board Certified Plastic Surgeon.  Pictures would be helpful as well.    Always look for a surgeon with lots of pictures and as if he or she is Board Certified by the American Board of Plastic Surgery. Good luck, Andrew Cohen, MD