my son rocks back and forth constantly

my 4yr old son has been rocking back forth since he was a baby he wont stop doing it. he just wont stop, he rocks all day he even wakes up in the middle of the night and rocks back and forth hitting his bac to the wall. is it normal?

[redheadaussie]

No it is not normal. He sounds to have possible Mild Spectrum Disorder. Known as Autism. You need to have him assessed by a professional. Many children like this are highly intelligent and often feel overwhelmed at the signals they are getting externally. Their brains are highly sensitive to just about anything; Noise, smells, temperature, etc. The only way they cope is to (usually) rock to and fro in a self comforting gesture. Often they can be trained to adapt to the situations, but if left can be difficult to manage for you at home.
All the best.