My 6yr old has heavy head. he finds relief by snapping his head backwards. he does this every minute. he says if he doesn't his head is to heavy to ho?

Tic: It may be a tic where he has a need to do a repetitive motion for a perceived relief. Or a habit. I would try and distract him so he does not do it and he may need to see his doctor if it continues

Behavioral Dysfuncti: You need to ask him more question about what may precipitate his symptom or if he remains aware of this while doing The first medical condition that comes to mind is Tourette Syndrome and other conditions such as Sensory Integration Dysfunction, or Epilepsy (Simple Partial Seizures.