I am experiencing tightness in the rear of my head followed usually by tingling sensation. What could this be?

Acute or chronic. If the symptoms have been of few days duration and progressive without relief then see a neurologist quickly. If symptoms have been intermittent for months then likelihood of cervical osteoarthritis causing nerve pinching is high. Still neurologist will be helpful.
Seek urgent care . I would recommend seeking urgent care to rule out any serious organic diseases.