I also am going to assume you have had this checked by a doctor,
Is your heart rate on the slow or fast side? Let’s say below 60 beats per minute? Or, over 75? For now, I recommend only laying down to sleep when you are really ready to fall asleep. When you will be tired enough to fall asleep quickly. My other recommendation is to get your thyroid checked. If your doctor checked it, look at the numbers yourself, make sure they are not near the edges of normal or outside of normal.
I have a heart arrythmia and when my thyroid is off I really feel the arrythmia when I am at rest. I feel like my whole body stops for that moment. Can’t breath in, can’t move, it’s like my whole body pauses. I go for months not feeling it when my thyroid is in “my” normal range, not to be confused with the larger lab normal range. If I am out of nornal I feel it every night, I even wake in the middle of night feeling I cannot get enough air and that I am going to wake up dead. My heart problem is considered completely benign, but I am much happier when I am not feeling it. I have no idea if that information applies to you, but I just thought I would throw it out there, you never know. Thyroid is often overlooked.
Also, check your iron levels, I would assume your doctor did check that.
See a cardiologist about it for sure if you haven’t. There are cardiologist that specialize in the electrical problems. Do not just rely on your GP. Also, don’t jump into any surgery if recommended, always get more than one opinion. Always remember, surgeons love to do surgery. They hope for the opportunity and they use any opportunity they can do it. Or, I should say most not all, but it seems like all.