Do you have any sores on your scalp? I had this same issue and was worried. I went to the urgent care and the doctor asked me if I had a sore on top of my head that I would pick at and not let heal... I was embarrassed to admit it, but it was true. After I put antibiotic ointment on it and let it heal, this went away.
I would have an ENT doctor check it out. Usually, if it moves, it's not serious. Check with doctor he may request scan. Good Luck