What pose/s are best for headaches? Tension headaches mostly.

Tension headaches are often associated with tightness in neck and shoulders, I believe. In that case, it would probably be wise for you to focus on easy stretches and avoid things like shoulderstand (salamba sarvangasana) and headstand (sirsasana). Postures that focus on lengthening the spine like easy pose (sukhasana) or mountain pose (tadasana) would probably also be good for this element of your practice. Cat/Cow pose would be really good, as well as wind reliever pose (pavanamuktasana).

Gitali

I have heard that the neck and sacrum are connected, so perhaps you will try some postures that release the lower back, like reclined twists, reclined cobbler pose, or pelvic tilts. Seated twist, or Ardha Matsyendrasana, could be good for your back. Also, if you try lying on your back and letting your head fall from side to side, that could help you release some tension also.

Matsyas

Definitely try some neck exercises. Dropping the chin down to heart center and then letting your head roll from side to side often releases tension. From there, you can keep you head to one side and gently rest the opposite hand on the side of your head, gently pulling your ear to your shoulder. Be careful not to pull your head down too hard or retain tension in your shoulders.

Deepa777