I understand your problem.
I would have helped you better if you have Mentioned your duration, weight and height.
Coming to the point that you have mentioned I assume that you are obese and the problem that you are facing is because of the excessive fat that has been accumulated there.
There are various causes for lump formation in the breasts but I want you to know that this not common in all the individuals.
According to my assumption if you are obese and with the problem that you are facing it is time that you need to consult a doctor personally and get it evaluated if you have pain along.