Had neck surgery monday to untrap a nerve and remove and replace c5, 6, 7 disks. since then been having a lot of major headaches. what could be the cause?

Trauma: Pain after surgery including headaches is not unusual. The anterior approach for disc removal and fusion is usually very well tolerated but sometimes the positioning of your neck and the spreading of the disc spaces can combine to cause the headaches you describe. Most commonly, pain referred from the cervical discs is between the shoulder blades. The headaches should resolve with time and meds.

Headaches after sure: The most common is neck muscle spasms and tightness along with post operative changes and inflammation. This is quite normal after neck surgery.

Depends: The three major causes in my experience are either muscle spasms that can go into the back of the head and neck and cause headaches, or an aggravation of an underlying headache problem, or there is a surgical complication known as a spinal fluid leak that can cause severe headaches. If it does not resolve soon, you should be checked. Thank you for your question.