ive been experiencing likewise for the past 10 years. i finally figured out what was drivng me mad: heart pounding, constant head pressure esp waking up. like a vice grip clamping down on my head all the time... and that clue was just it.. a vice clamp, which was me CLENCHING/GRINDING my teeth at night. since realizing this my only method for a cure was just that.. being aware of what i was doing. i just catch myself when i feel like clenching and even when im sleeping i have it undr control. tell yourself not to grind or clench during the day or sleep. if that doesnt work, try a night guard. however i havent needed to buy ine of those b/c i have good self discipline. clenching and grinding ur teeth at night can really make a person go nuts. research it, its called bruxism.