What causes a headache?

Does smoking ciggaretts causes headaches I heard it was lack of sleep.

Yeah because I'm confused on how you get headaches lol. does anything like trigger it? and what exactly hurts inside of you h...

So for the past few weeks I've been getting this reoccuring headache mostly on the right side of my head. Sometimes the heada...

I had my wisdom pulled, so I haven't really been able to drink coffee much. I started drinking it just now, and I have a head...

I've been getting a lot of headaches lately, I think they might be migraines. They get to the point where I cant even look at...

long story short I have been crying all night and well into this morning...my eyes look like hell and my head hurts so bad!!!...

Just wondering if its true that caffeine causes cellulite? Because I think I heard that somewhere. Lol just wondering.

What are some injuries that causes heterochromia?

Can crying cause headaches?

Will nitrofurantoin macro cause birth control pills less effect? Can I drink alcohol when taking nitrofurantoin macro?