How come i have to crack my neck every 5 seconds?

Just you: This is just you. There's no significant underlying physiology to tell you about - your body just likes to do that. Fortunately, i'm not aware of any studies proving that this is a bad thing in the long run.

Problem elsewhere: When a pt. has to crack their own neck frequently, it is usually due to a feeling of stiffness or pressure.Strangely, the problem is actually usually found in another part of the body, esp. the lower spine.In my osteopathic practice, I often see that finding the real area of restriction, ligament inj or spasm & treating w/Manipulation, prolotherapy, or such completely stops the need to crack.