I have a pain in my head that I remember when I did dxm it'd like a rock and when I move my head dosent move as fast and makes the rock feeling more apparent since I then feel it on the back of my skull. I only put dxm or robitussin cough syrup in this post because that's when I remember the feeling I'm feeling in my head. What causes this uncomfortable feeling in my head and is it related to serotonin like I think or is it something else. Also if it is serotonin related will this bottle of 5-htp I have fix it.