Hi there -
Rather than a blood vessel being temporarily trapped (wouldn't feel the way you'd think it would) this is probably a nerve being trapped or plucked for a moment, and it may well be due to temporamendibular joint (TMJ) problems. Often we don't know we have such a thing going on, because the symptoms are often away from the jaw and sometimes not seemingly related (headaches, dizziness, pain in the head when yawning, etc.). TMJ problems can be caused by evolutionary changes, nocturnal tooth grinding (bruxism), trauma, dental misalignment (often very slight), etc. This seems the most likely cause of your head pains. The later headaches could be unrelated -- or not. It's hard to know. If this is due to TMJ, then the headaches may also be related. Often a dentist is the one who discovers some evidence of the problem and is a good starting point for trying to uncover the cause.
Hope this is helpful. Good luck to you.
John Kenyon, EMT, CCT
Non-invasive cardiology tech, Emergency and Critical Care technician, Critical Incident Stress Mgmt. specialist