If you're spending a lot of time on the computer every day, have you had your eyes checked lately? Are your eyes red or dry? It could be something as simple as eye strain. Try some eye drops. Sometimes optometrists will prescribe special glasses just for computer use. You don't wear them to read or to drive, just while at the computer. My friend had a pair with coloured lenses just to wear while on the computer.

Or, are you grinding you teeth at night? I had a dx of TMJ in my 40's. I had massive headaches and my dentist found I was grinding my teeth at night from tension and I didn't even know it. He prescribed a mouth guard (which you can get at the dentist for $300 or at the drug store for $5) and I quit grinding my teeth and the headaches went away.

Carpal tunnel syndrome can also cause headaches. I had left and right carpal tunnel surgery in 1994.

Many simple physical things can cause headaches.