Has anyone experienced an underlying heart condition that caused sleep problems (UARS + TMJ) in a young body?

Note: I've been meaning to see a cardiologist, but my PCP is a gatekeeper who's been putting me off (Kaiser HMO plan and I'm 19m -- me being "so young for heart attack" is why she's not giving me a referral).

Context: 19m, 6'2, 180lbs. I've been having sleep problems for 8+ months now, and while I thought the core problems were anatomical, I'm starting to think there's a heart piece related too.

History: My maternal grandpa had multiple heart attacks + pacemaker, and paternal grandpa had stroke.

For at least a year, I've had symptoms of UARS + TMJ (insomnia, chronic fatigue, jaw scrapes, cold hands and feet, etc.).

However, one thing that doctors are surprised by as I'm doing consultations for surgery (MARPE / FME / MMA) is the heart symptoms I'm having. 

These include heart palpitations, nausea, sudden tightness in chest, and shortness of breath.

I'm looking for some perspective on this.

• Has anyone here experienced similar symptoms that were initially brushed off due to age?
• What did it end up being?