Chronic non-migraine headaches?

For 3+ months I have had almost daily headaches varying in intensity and location. Some of them were at the back of my head at the top of my neck. These were pretty sharp pains that were only relieved if I put pressure on that spot. Some have been more generalized just an all over ache. Some have been localized to the left or right part of my head and persistent aches. Lately, it's been a stabbing pain that would occur every couple minutes and last for a couple seconds then subside for a couple minutes. It's enough to make me flinch and grab my head every couple minutes. While none of these are migraine-like to where I can't function, it's highly uncomfortable and I'm worried because it's an almost daily occurence. I haven't noticed a sensitivity to light but it does get worse with even a slightly loud noise. I have been kinda stressed lately but no more so than I have been for the last 2 years. What could be the cause?