Given that the doctors have run a battery of tests on you, and have come up with nothing serious, I'm surprised they haven't mentioned hyperventilation syndrome to you. Frequent yawning and sighing respirations are very common symptoms of this quite common syndrome.
For some unknown reason (possibly ANXIETY or even something as silly as wearing pants too tight (!!)), you stop breathing from your diaphragm and begin breathing in your upper chest. This causes hyperventilation.
When you breath in your upper chest, you can't get enough oxygen to the lower parts of your lungs. You breathe shallowly.
When you breathe shallowly, you need to breathe more often to get enough oxygen.
When you breathe too often, you exhale too much carbon dioxide.
When you exhale too much carbon dioxide, you hold your breath a lot to keep the level of carbon dioxide in your blood from dropping any further.
When your carbon dioxide level is low, your blood circulation is affected such that you don't get enough oxygen to your brain. Also, the pH of your blood changes.
When your blood pH changes, the muscles that wrap around the blood vessels may spasm.
When you don't get enough oxygen to your brain, you YAWN a lot, some people even get dizzy, and/orget headaches had lose concentration, get easily fatigued, and all sorts of other things .
To sum up...(hope I'm not getting too repetitive here!)
Your breathing is regulated by your brain. Normally, when it detects a high level of carbon dioxide in your blood, it sends a signal down a special nerve to your diaphragm, telling it to contract. .This creates a vacuum below your lungs and you breathe in to fill the space. When you breathe out, you exhale carbon dioxide, presumably returning your carbon dioxide level to normal. Sometimes your brain causes you to yawn to get extra oxygen in and extra carbon dioxide out.
When you breathe in your upper chest for an extended period of time, your brain stops sending signals along the nerve to your diaphragm and just triggers your ribs to expand instead. THIS IS PROBABLY WHY YOU FEEL THIS WEIRD TIGHTNESS IN YOUR DIAPHRAGM... Now you "normally" breathe TOO SHALLOWLY.
If your carbon dioxide level remains low for an extended period of time, your brain "resets" to make your current low levels become "normal." So now your brain causes you to breathe at an abnormally low level of carbon dioxide, thereby keeping your level low.
It has become a self-perpetuating situation.
It really does sound like anxiety is the culprit here. There are breathing exercises that help one "retrain" themselves to breathe properly from the belly instead of the upper chest...Ask your doctor about it. There are even books on proper breathing and how most of us are really "chest breathers"....
Are you seeing a psychotherapist by any chance? If so, they should recognize this easily and help you "learn" to breathe properly again!
If the paxil kicks in and your anxiety level drops, then these sensations will go away on their own.
So, try to relax.....this is truly very common and underdiagnosed.
[This message has been edited by zuzu8 (edited 07-14-2003).]