It sounds a lot like anxiety to me also. However, I really think you should have some medical testing done to rule out any other problems. You should ask your doctor for a chest x-ray, labwork and an EKG. Otherwise, you will never know for sure. If these tests come back normal, then you might want to try the treatment for anxiety. I'm not sure why he would suggest Zoloft rather than Ativan or Xanax since Zoloft is an antidepressant where the other two are anti-anxiety medications. Are you depressed also?