I woke up this morning feeling normal. later on i turned ny neck and heard something break. my neck has been stiff since then. what could be the cause?

Small joints in neck: There are small joints on the backside of the spine that can crack similar to cracking your knuckles. Try gentle range of motion exercises including extension, rotation and gentle flexion. If this does not help over the next couple of days or if things get worse then you should see a physician.

Vertebral dysfuncton: Vertebrae in the neck have joints which often 'pop' even w/out pain, when bending or twisting.Occasionally, tiny muscles which move the vertebrae spasm after a 'crack' causing pain, keeping the vertebra bent or twisted.Eventually, larger neck muscles 'splint' to stop the vert. from moving-causing more spasm & pain.A good osteopath or chiropractor is trained to manipulate & fix such problems.