Why do my implants harden when I lie down? (Photo)

I had my breast augmentation 11 months ago. My left breast was like A cup and my doctor use 300 cc on there and 250 cc on my right breast which was a B cup. My bigger breast softened really quick as it has more fat tissue but my smaller breast still firm and stiff especially when I lie back down. Ofcourse there’s been improvement since the operation but it feels like a rock when ı lie down. Also, my bigger breast becomes so firm when I lie down on a ground. Can it get more naturally soft?