So I'm sleeping on the train and my head drops (no contact with anything) I immediately wake up because the front of head starts hurting. Later on it feels swollen in the front. I notice my pupils start dilating and undilating. So I took some aspirin. This has happened to me more than a few times. Nothing major but I'm wondering if I've had more concussions along the way than the one that caused all this? I've had PCS for about 10 months now.