Positional plagiocephaly happens early in life when the child is unable to hold his neck and keeps the head towards one side. It is normal in infants. Your child is still very young to correct it. As per your photos your baby looks developmentally normal. You will have to keep patience until the child learns to sit on her own.
Next Steps
1. Keep the child active, allow him to play freely, avoid laps wherever possible. Build a safe play area for the baby so that she can play freely.
2. While going to bed, check if the baby keeps her head towards mother so that she feels comfortable. If yes, you can change your side on the bed or just allow her to be in her own bed, whatever suits you.
Health Tips
Nothing to worry, just give it time. No added investigations or therapies needed.
Best wishes