Hello and thanks for your post
It's not unusual for one breast to be slightly bigger than the other.
Unfortunately, we cannot tell you what the matter is. But it is likely to have a straightforward medical explanation. However, it's a good idea to go and get checked out by your GP just to be on the safe side. They will assess you and decide if you need to be referred to the breast clinic for further assessment. This might seem worrying but the majority of people referred to the breast clinic do not have cancer.
I hope you know more about your situation soon.
Kind regards,
Celene