I have ache in my back side of the neck. i can see small hump, can that be spondalitis? i am using flat head pillow in the night.

Spinous process: The lump you feel on the back of your neck is the spinous process. The most prominent one that you can feel is at c7. You might have spondylolsis but x-rays and imaging would be best to make the diagnosis.

Nope: Spondylitis is internal, in the spine joints themselves. You can't see it from the outside. More likely this is soft tissue, fat, or similar.