Stress can do alot of harm to an otherwise healthy person.
I suffered severe stomach cramps, diahrea, dizziness, nausea, headaches and sweating all as a result of extreme stress.
Many people think that stress just affects you emotionally and mentally, that is not true. It can manifest itself physicaly and cause many strange and even painful symptoms. These symptoms are your body telling you that you need to take a break from the stress and relax and rest before you have a nervous breakdown.
I too consider myself a hypochondriac, and when I had these symptoms, I would look up on the internet and have myself convinced that I had this disease or that condition, I would demand my doctor to perform costly and sometimes painful procedures and tests to prove that I did have something, the whole time he was telling me to relax more and remove myself from stress.
Well, I am a little older and much more wiser now, and when these symptoms appear from time to time, I listen to my body and try to relax and rest more. Meditate and do breathing exercises and remove myself as far away from stress as possible.
I am sure that aside from stress, you are perfectly healthy, and should feel lucky to be so. Find some relaxation techniques that work for you and you will notice these symptoms to disapear.
good luck to ya!