Is this my heart and/or arrythmia?

[JZ781]

Every single night for past couple weeks. Right as I fall back asleep I am instantly woken up to what kind of feels like palpitations, but more like a rumbling feeling, kinda like sn earth quake, i feel it in my chest, and my head neck etc. its not aligned with a specific time, but rather whenever the minute begins that I fall asleep. It doesnt last long and my pulse feels normal, iphone app had a HR of 81 when I was able to check, no pain, if i take a deep breath it feels weird and slightly short on breath, dont feel like suffocating or chest is tight and gasping for air. I have issues with PVCs some days, not every and what I can feel theyre double digits daily (is it poaaible having some you feel and dome you dont)? 6 mos ago chest x ray, echo, blood and 2 heart monitors all came back negative besides pvcs. I just hate this feeling, cardio appointment tomorrow, any input before I go in, any tests I should request? Thanks :(