Breast reduction I am 33, without children I have constant pain in my neck, back and shoulders and very bad migraines which I'm not sure if that can be a factor as well. I am considering breast reduction surgery I know I will have to quit smoking before

Reduction helps. Breast reduction surgery has been shown to significantly improve or relieve symptoms of head ache, back ache, neck pain, shoulder pain, etc. Somewhere around a pound or more of tissue needs to be removed from each breast to have an improvement in symptoms.
Stop Smoking. Nicotine behaves as a vasoconstrictor of vessels thereby decreasing blood flow to tissues ( that need to receive blood flow to heal after surgery).  a decrease in this blood flow may result in wound healing problems and/or tissue death. Patients should avoid forms of nicotine ( smoking, gum, patches), especially prior to procedures involving flaps such as breast reduction, tummy tuck, facelifts.
Good idea. Large fallen breasts can contribute to all of those symptoms. A reduction should have a significant improvement on all of the above.
Breast . Breast reduction surgery for women who have large breasts and suffer from chronic neck, upper back and shoulder pain is certainly a reasonable possible course of action, after other courses of action have been exhausted. It often makes the muscular headaches better. It does not unfortunately improve migraine headaches. That will need further evaluation and is often improved with medication, diet alteration, and avoiding migraine triggers. Mammography or breast ultrasound is a very reasonable test due to your strong family history of breast cancer. You will need to speak with your physicians and insurance company to see if this is a covered benefit. Remember that a test may be reasonable but still not covered by your insurance company. You might need to be forceful. Hope this info helps.