What coul cause all of these symptoms?

I have been experiencing a wide variety of odd symptoms recently.  First, I experienced bloating or a feeling of fullness which made it hard to breathe especially when was laying down.  I also became very intolerant to heat and often found myself in a neer panic attack in stressful situations. (Very uncommon for me)  I had an abdominal scan and the Dr. found enlarged lymphnodes, but did not think it was serious.  Those symptoms have gone away for the time being but they have come and gone for a few years and seem to be worse each time they return.  Now I am experiencing a feeling that my throat is closing.  I am fine in the mornings, but as the day wears on it gets worse.  Each day is worse than the one before.  It is also accompanied by a stiff neck.  This happened a few months ago and my neck got so stiff I could hardly move my head, and then one day I woke up an it was gone.  My panic attack-like situations have returned and I find it hard to concentrate or remember things and seem low on energy (also odd for me).  Anyone have any idea what might be going on, or if this all may be related?