Hi medmystery - I have the same problem. For me, I think it's a hormonal imbalance. Although I'm now 44 years old, I've had periodic periods of chest pressure throughout my 30's as well. Unfortunately, it came back this summer (along with some other extreme symptoms), and I ended up in the ER 4 times. I feared I was having a heart attack or stroke. I have undergone a miriad of tests, i.e. CT scans, MRIs etc. to see if I was having adrenaline or cardiac issues, all of which came back negative. Tests on my hormones have also come back negative. My blood pressure would spike (186/126) then drop dramatically, which was exhausting. In addition to the constant chest pressure I sometimes feel like I'm out of my head (hard to explain) and just generally not feeling right. My doctor says that the chest pressure is anxiety. I asked my doctor if my strange unexplained physical symptoms (i.e. headaches, body rushes, erratic blood pressure, rapid heart, intermittent insomnia, sweating only at night) could be perimenopause, but he didn't think so (I don't agree). I'm not depressed or feel anxious. I'm physically fit, don't smoke, drink excessively, etc. I'm now on blood pressure medication and Effexor to try to settle the wierd, intense physical symptoms I was feeling earlier this summer. I feel absolutely fine now, except for that darned ever-present chest pressure. Now that I'm convinced I may be starting perimenopause, it doesn't bother me as much anymore. Other women's web-forums say that they've also gone through this and it may last a few years (ahhh!). I hope you feel better soon.