Swollen at night time - 2 weeks post op lift and implants.

In the morning my breast feel swollen for 30 mins once i start moving it goes which i know is normal. However at night time (say from 9pm onwards) they start to feel more swollen and heavy again - Im still sat upright even if its on the sofa and walking occasionally but every night they get more swollen and firmer. Is this normal and if so, why? Thank you!