I get the 'dizzies' sometimes as well. It can be scary, but I have never actually had anything happen as a result of this symptom...other than feeling like I am on a storm tossed ship.;p
Have you had any success with breathing techniques? I find that if I do some deep breathing exercises that this corrects the issue for me almost every time. (this Sx is often the result of shallow breathing/hyperventilation)
This is my go-to breathing exercise. It is the only one that really ever worked for me. See if you find it helpful.:)
The Divided Breath:
Imagine your lungs as having 3 parts. The bottom third, the middle, and top third. On the inhale fill the bottom third first, then the middle and finally the top third. Make sure that this is one continuous breath, but divided, with a slight pause in between each third. Hold the breath in for 3-5 seconds if possible. Exhale in reverse. First blow out the top third, then the middle, and finally the bottom third of your lungs until all air is expelled. (remember the pauses) Repeat several rounds for a toatal of about 10 minutes. Practicing this every day will not only give you control and structure to your breathing, it will strengthen and loosen the thoractic muscles, allowing better, more productive breathing, and relieving the chest tightness!
S.C.