First of all, an in person consultation is needed to know for sure what can be done, that being said you have a number of options. One is weight loss -- you will decrease your over all fat - the other would be some sort of breast reduction and fat removal. Both depend on the in person consultation. Things can be done -- but weakness of your arm is unlikely from the excess fat. Exercise will help with that.
The photos are very limited in what they show. There are several options with the asymmetric breasts, it is just a matter of what you prefer. More details about your history are important. What is your height and weight? Any medical issues? etc.. An exam in person is key.
I usually treat lateral breast fat with liposuction. This should be done when you get your breast reduction. I recommend an in-office examination as well as a detailed discussion with a surgeon who you are comfortable with and who is a board-certified Plastic Surgeon certified by the American Board of Plastic Surgery.
Harvard Educated, Beverly Hills & Miami Beach Trained, Double-Board Certified Plastic Surgeon
You should be examined to determine whether that is, in fact, fat as opposed to ectopic breast tissue which would require excision as opposed to liposuction. In terms of the breast asymmetry, photos of both breasts would be helpful as, frequently, both are operated on to achieve symmetry both in contour and in nipple heights/size. Best wishes.