Migraines are not typically neck generated but I believe you mean constant type headaches that originate from the neck that “feel like migraines”.
The constant pain at the base of your skull could be from facet inflammation, actual degenerative joint disease (wear of the cartilagenous surfaces) or from nerve compression. The other symptoms you express can be from vertebral artery problems but that would be an extremely rare finding.
You don’t typically get hypermobility of the upper cervical spine from sports activities (unless significant trauma is involved) but more commonly from genetics.
Before you consider any surgical options, you need a diagnosis. Many times, this condition is treatable without surgery.
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.