Heart :: At Night Vibrating, Short Of Breath, Aching

For a couple of years now I've been having weird behaviour, episodes, happening with my heart. I've had a heart murmur since I was a teenager, caused by hyperthyroidism that went undiagnosed for too long, so heart issues for me aren't new, but this is different. They seem to happen primarily at night, I wake up feeling short of breath, my heart feels like it's vibrating more than beating, my chest and limbs ache, especially my arms, but it's not a stabbing pain, just feels like really tense muscles. It leaves me feeling the next day like I have a cat sitting on my chest and very tired, and often within a couple of days I notice splinter haemorrhages on my nails, up to 6. I've had numerous tests, ecgs, an echo, week long ecg, stress test, thyroid test, iron test, MRI. Nothing has come back conclusive, I've been told it's just a heart murmur, that it's probably just anxiety (then why is it hitting me when I'm sleeping? and since when does stress cause splinter haemorrhages?), that splinter haemorrhages are nothing are not proof of anything. A bit of background, I'm almost 40, it's been happening for 2 years, 6 months after I got a copper coil, 3.5 years after I gave birth, I've had hypothyroidism for 5 years, but had hyperthyroidism up to 3 years before that, I have a strong family history of heart disease on father's side, (but I don't have the high blood pressure they did, I do have high cholesterol though, but not severely) and low iron on my mother's (I've been taking supplements since a test many years ago found me low on this). This seems to happen when I have my period, but not with every period, and does pass, but eating a poor diet and little exercise also seem to effect it. Anyone have any ideas? Mine have been: low iron, thyroid storms, Prinzmetals angina, cholesterol floating around my body, a blood clot condition causing small clots to float around my blood periodically affecting my heart, lupus, or, my body reacting badly to the copper coil