Carvical rotation/Neck rotation

Bones, joints and muscles
1

Hi -

I am 30 year old and I have a problem from childhood. I cannot rotate my neck more than 40 degrees both sides even I don’t have any kind of neck pain or muscle pain but just cannot rotate.

Can any one suggest me why this is so and how to improve it.

I did few exercise before but not so effective

2

Can any one tell what’s the problem and how to get ridged out of it ?
Does any one have same problem like me ?
Please suggest