I am 38 and have had this same thing on and off for over 2 years. I too suffer from Anxiety, I had my first bad attack 5 years ago and have had several since then (My mom had her anxiety start in her early 20's, my Dad has had Panic attacks since his 30's and my sister also since her early 20's), and I also have GAD. I have had the pain in the left side of the ribs alongside my sternum in one spot, and pain in the back below the shoulder blade, it is very irritating and also scary when it hits. I have had, Stress tests, chest x-rays, EKG's, blood work and general workups all of which found nothing and the dr.'s say it is all caused by stress and anxiety, I still obsess over it when it comes on, it really drives me nutty and I have convinced myself it is either chostochondrtitus or lung cancer (since I smoke, although I have no other symptoms except for the the ones I mention). It drives me crazy since it starts for no reason and disappears for no reason.....I can go a month without pain then have it comeback and last a month....I keep trying to convince myself it is costo and take my xanax when my mind starts to race, but find myself googling the medical sites to try to find an answer. I am glad to see someone else is dealing with this as well....and that I am not going crazy. I am really trying to cope and tell myself that my brain is convincing me to have even more symptoms....but its real hard to try to convince myself otherwise. Has anyone else had this as well....my chiropractor says its all stress realted and nerves, and that I should also watch how I sleep at night and make sure I am not pinching my neck or chest in a weird way...it seems to help a little, he also says that poor posture affects the nerves in the neck which lead to the ones in your chest as well....am I just paranoid or is it my anxiety or all of the above...????