This Forum deals only with breast cancer issues,and the pain you are describing does not indicate that you have this disease,especially because it's occurring on the sides of both your breasts.In my opinion,if you don't have any symptoms in your breasts,like lumps,nipple discharge,skin thickening, swelling or redness,then this has probably something to do with muscles problems or a pinched nerve somewhere in your back that could make the pain radiate around your chest and armpit.
My advice to you would be to see your health care provider for a complete check up to find out exactly what is causing the pain you are describing.
In the meantime,you could post in the "Pain Management Forum" that deals with all sorts of pain.I think that you will be better served if you posted there.
Hoping that you'll find relief soon and I am really sorry if I can't be more helpful to you...
Please click on the link below.