Please check the eligibility requirements of your insurance plan first. These are usually posted on their website and include the Company's rules on how many grams (weight) per side should be resected, as well as their recommendations on whether you have "failed" conservative therapy (such as physical therapy, weight reduction, utilization of support bras, etc.). The Company's may also have a position on your BMI (Body Mass Index, weight in kg/ heigh in cm), which must conform to their position. These are the usual parameters required for patients with heavy breasts who wish to have reduction surgery to address their musculoskeletal symptoms.
In your case, you mentioned that your discomfort had been somewhat alleviated by the original procedure. Try to enlist your primary care physician to intercede on your behalf by writing a letter in support of the discomfort you have in the scar line. Also ask him/her if they know a Board Certified Plastic Surgeon, who has an active practice which includes breast reduction, who is also on your plan. By building a case and using "preferred providers" you may get some financial assistance. You may have to attach photographs to support your petition. Good luck.