Hello, Doctor. I am having a tightening feeling in my chest area--above my stomach--in the mornings just after I wake up. I will be awake for just 4 or 5 seconds and I feel a sort of squeezing feeling, as if my blood pressure is trying extra hard to rise. I am 50, female, don't smoke, I weigh about 143, and I exercise fairly hard 3 times a week. I have low blood pressure--sometimes in the 90s on top and 50's-60s on the bottom. I never feel faint or dizzy or have chest pains. When I get out of bed following this tightening, I'm not dizzy or lightheaded. What do you think this might be?