Shrinking breast

Hi. I’m new to this forum. Has anyone experienced breast shrinkage? I noticed a few months ago my right breast was smaller than the left. I wasn’t too concerned but over the last 8 weeks I have noticed a considerable difference in both breasts with some breast & collar bone pain. Was at GP re another matter & I mentioned this. She examined me. No lumps or anything obvious but said she was referring me to breast clinic as non urgent.

thanks Hazel x