Im guessing you are right handed like me!!! I had my BA 8 Days ago and my right side is still slightly more swollen than the left. Honestly hun dont worry, I was much more swollen on my right, the nurse said its because sub-consiously i do more with my right arm being right handed. Mine are pretty much the same size now, the difference isnt noticable to other, only to myself!!!
Give it time, you are only 2 days post op, give it at least another week because panicing!!!
Happy healing xxxxx