I hit the back of my head on new years and have been getting frequent headaches since. Is this a problem?

Could be. Frequent headaches following a head injury could be a sign of post-concussive syndrome. This is definitely something to get checked out with your doc. If you hit your head on new years, does that mean you have had these headaches for 11 months? Be sure to see your doctor about this.
Yes. This is almost a year post trauma. Not sure if you were seen back on new years for the accident at that time. But it appears that your symptoms have remained or become worse. I would not hesitate to be seen by a doctor asap.