Adjust the straps to a comfortable position and make sure the back adjustment is snug without being too tight. The cups of my bra wrinkle. Cups should completely contain each breast. The cup is too small. The bra is too large.
All women have one breast that is larger than the other.
Sometimes the difference is noticeable, most often it isn't. If the difference is significant, try a bra with stretch fabric in the cup or a bra with fiberfill. Also, you can adjust the strap so the larger breast is looser than the smaller breast strap. Always fit the cup size to the fuller breast first. My bra is very uncomfortable, cutting and binding when I move.