What could be causing intermittent localized pinching head pain on the left side? spot is the size of a quarter and slightly tender to the touch.

Infected cyst: warm soaks to area 5-6 times daily if pain increases see a doctor.

Nothing serious!: The kind of symptom you have implies that there is nothing serious going on in that area. I would not pay much attention to it as it is likely to go away in a matter of few days whether you do anything to it or not. if it bothers you, you can put some Ice on it once/twice a day(cover ice in a paper towel and let it soak through the paper before you apply it to the painful area of scalp for 5-10 mi