Sorry, but your head, as in your skull, isn't a joint. You can only sprain joints, [i.e. Knee, Hip, ankle]
Sprains and strains can be prevented by warming-up before exercising, using proper lifting techniques, wearing properly fitting shoes, and taping or bracing the joint.
Ligament (tissue that connects two or more bones to a joint)
yes i have experienced the spraining of ones buttox and i could not have sexual fun for a few weeks :(
yes you can. usually while playing sports. the severity varies. you could have to get it X- rayed or even get an MRI.