I know exactly how you feel. I feel breathless today so I think I have lung cancer or something else. If I forget something oneday I think I have the onset of dementia, or If I have different mood swings I think I have the human form of Mad Cows Disease!! The list is endless and in the past I have spent hours on the net loking for symptoms and what they could mean!! I am trying not to do this now though because I've decidd if I keep thinking something is wrong with me, I'll have wasted my life!! There are so many bad things that could be happening to you, you just have to be grateful they're not. I know its easier said than done, but don't waste your life trying to find something wrong, be happy nothing is!! And remember about cancer, there also lots of people who beat it, but you don't tend to hear about them, people only talk about those which die, and thats becoming less and less these days. I guess what I'm saying is don't look for something to be wrong with you, stuff will always come along to knock you off balance, but one thing to always be grateful for is your health, anxiety and panic are soul destroying but after many years of experiencing it, it must make your more positive that nothing else has developed, you can see that it is only anxiety. That tight chest is not lung cancer, and the racing heart is not a heart attck, its horriable when it happens, but it won't kill you. I once read a quote which has often helped me when I've felt a panic starting, " What happens to us is not what is important, its how we react to it!", If your chest feels tight, don't go to the doctor, remind yourself its only anxiety, don't let it beat you. I think I've rambled but I hope I made sense, I just wanted to let you know I know how you feel, but don't let it beat you.