My boss (Dentist), tells our patient about my "aches and pains", during the exam. Is it against Hippa to discuss anything related to my health issues with another patient, or is this a privacy issue?

If your boss is treating you for these aches and pains, then yes it is a HIPAA (not HIPPA) violation. But since he's a dentist, its not clear whether he's actually treating you for them.

If he is not treating you and you have volunteered the information, then its not a violation of anything but your trust. Did you ever say that what you were telling him was in confidence? My suspicion is that he was trying to set his patient at ease, but that doesn't excuse him. Have you told him you don't want him discussing such things without your permission?

It may be a privacy, but then there is nothing illegal about that, it is just not considerate and not proper for a boss.

If as noted, he is your doctor, and the pains he is talking about has to do with the medical treatment he has given you, then it is a HIPAA violation.

If you don't like the boss gossiping about your business tell him to stop, but I doubt what he is doing is a HIPAA violation, but it is unwanted.