Worried

I am 37 years old and for the last 2 months have noticed odd symptoms. Since I finished breastfeeding my L breast has been noticeable smaller then the R breast. Now it is noticeable larger then the R. I had felt a lump and have had pretty constant discomfort in only my L breast. I am deployed for the military and finally went to a doc last week. He referred me to another doctor who has since sent me to a Germany for a mammo and Ultrasound. In the area I had felt the lump I sometimes feel like my milk is letting down. I haven’t nursed in over 3 years. I also have nipple soreness. I don’t know if this make sense but my L breast just doesn’t feel right. I am hoping to get my mammo and ultrasound done tomorrow. But thoughts? Is it possible for cyst to cause these symptoms?