I keep having tightness and tension at the back of my head down to my neck and jaw. i don't know what it is but it makes me wonder what this cause could be. it's doesn't feel like a headache migraine so what is it?

TMJ?: You describe symptoms of muscle tightness and tension. The distribution suggests that it is involved in the jaw muscles. This can be associated with disorders of the temporal mandibular joint (tmj). That is where the jaw connects to the bones near the ear and neck. A thorough medical evaluation including dental x-rays and neck x-rays would be appropriate.

Depends: So many questions and answers are TMJ focused. The jaw joint is the most complicated joint in the body & while it is well understood anatomically it is far too often implicated in vague diagnoses. It could be some joint dysfunction, but just as likely not. Do you sit and work at a PC for hours on end? It could be postural. In these times of PC over-use, it does cause many muscle aches. My 2 cents.

Neck &jaw tension: This sounds like symptoms of bruxism (grinding or clenching your teeth). This can take place at night when you sleep, and also at various times during the day. If at night, you should wear a nightguard. If during the day, you need make sure that your jaw is relaxed and your teeth are not held together except when you are eating. It's best if you check with your dentist.