some questions

[addictions101]

i am a 29 year old man who is 5'10  245 pounds, i went to a cardiologist about  my symptoms,  which are   a heavy and tight feeling in the middle of my chest up to my neck, which makes me feel tired and weak, and hard to get a refreshing breath of air.  I also get heart palps in this same spot, most of the time they are post-exercise palps but not always.      Sometimes I'll have a good day, or stretch of days when my chest isn't too tight, I have my energy back and I can breath really good.   But some days are so bad that I have a hard time even wanting to leave the house because of that and I'm so lightheaded constantly.    
There has been at least 3 occasions where I thought something bad was about to happen because I felt so weak, my heart was squeezing too hard, and I got very pale and clammy and nauseated, but it always passed.
Before all this started about 5 months ago I had a few occasions where I had a very uncomfortable yet vague pain that traveled around my chest/neck/upper back.    
The tests I've had have been nuclear stress test, echocariogram and xray of my chest.  And my labs were also normal.
There's a couple of things I was wondering...why did I not get a stress echo, should they have done this?   Since my other tests were all normal,  what should I get done now because this is def. not normal in any way.    
I will be doing an event monitor starting in a few days, but what else besides that should I get tested for?
I have though that if anyone can figure this out it would be a cardiologist, pulmonologist, or endo doctor in that order.  Should I see anyone else?

Anything u can add would be appreciated  thanks.
PS--Isn't constant or chronic lightheadedness a good indicator of heart problems or impending ones? especially since my labs were all normal?  I am just so lightheaded allll the time along with my other symptoms.

[Cleveland Clinic]

Given your age and the tests that you have undergone, you are at low risk for having severe or life threatening heart problems. I would suggest a CT of the chest to rule out definitively pulmonary issues, and perhaps a Holter monitor to document any heart rhythm issues. You may also consider a tilt table test, but this is more likely to help if you are experiencing syncope ( that is passing out.)