Head is usually 5 to 7 kg. And neck is comparable to the core of a toilet tissue. It can be compared to the core supporting a 6 kg watermelon.

Neck problems have become common these days because

1. More people tilt their head forward and down to see things (e.g. smartphones)
2. and maintain that posture for a prolonged period of time.

Such bad posture will put 27 kg or more pressure on the blood vessels and skeletal structure around the neck.