I see that you are at 178 and 5'3'' ... you still need to lose weight and fat to lose the back fat, unfortunately you cannot spot reduce ... A squeaky clean diet, cardio and weight training, in that order are what are needed.
Also, not sure how old you are but as you age, the fat seems to deposit in the back under the bra
go figure... My girlfriend super lean and skinny works out like crazy cardio and weights still has back fat, she's 50...