Anyone else experienced this, so my 10 week old baby seems to have very strong neck muscles, holds her head really well while sitting. However when lying down she always seems to be arching backwards with her eyes looking upwards - does this in her pram, moses basket, cot and on her baby gym. She's quite happy as I thought it might be reflux (constantly bringing up milk) but she doesn't seem in any pain. She also used to raise her head while lying on tummy but will not do it any more. Is it normal or should I be worried?