Hi...Londres gave u info on what it is , but I wanted to add how u can get it...many times it can be how u hold urself, posture...like soldiers..in fact the loss of lordosis is often times called soldiers neck.The other way u may develop this could be whiplash from a MVA.
If it is from whiplash many times PT can help relive this and restore some of the natural curve.
Do talk to ur dr about this.
Good luck
"selma"
Your cervical spine has a natural curve; lordosis, which helps with support. This curve is noted in the back of the neck. In your case, the cervical spine has straightened and at c4 and c5 there is a curved area noted in the front of the neck.
Are you seeing a Orthopedic Specialist or a Spine Specialist for this?