Hi,
I agree with everyone else, it's probably that you slept wrong or stress, and yes, you can get a headache from that. I woke up this morning with a headache and neck ache and know that it's a combination of stresss (upcoming test for school), and sleeping for too long. I've had insomnia the last two weeks, and last night I was exhausted and finally fell right to sleep when I went to bed and slept for 10 hours! It's made me feel headachy and kind of funky in my head and my neck hurts too. I get this all the time. Usually taking tylenol doesn't really help with it either, just have to put up with it for the day and will feel better tomorrow. Check with your doctor tomorrow, or call again later if it gets worse, but I think you'll be okay. Take some deep breaths and find something to keep your mind occupied...sometimes a hot bath with help relax your muscles. Hang in there, you're okay!