When biting down onto something hard, there is an audible click in my jaw, whereafter i cannot open, nor close, my mouth, accompanied by pain in temple and ear.

Joint blockage: There is a very thin piece of cartilage that sits between the jaw bone in the joint in front of the ear and the skull. From your description, the cartilage has moved and now is blocking the normal movements in the joint. This blockage can cause pain and poor opening and closing of joint. You should make an appointment with a board certified oral and maxillofacial surgeon to evaluate your joint