heart race pound on bed from changing position?

[KisekiShiawase]

Hello i hope i get some shed of light here :(
I have a history of heart problem (tachycardia palpitation) since i was a child (means its been more than 10years) i thought it will get better or go away but unfortunately that was still a dream for me. the cardiologists ive gone into just put me on beta blocker (which i found out could cause bad side effect) and it wasnt helping so much i still cant be normal. so ive been leaving through hell and abnormal life because of it. which i hate. the problem is the cause of my symptoms still unknown.

to make long story short.
a week ago i visited my cardiologist cause i got tachycardia and palpitation every morning for almost about 1-2 weeks so i ask about my other symptoms and mention could it be dysautonomia? but he just brush me off. when i search it online i noticed some people experience it too and mention dysautonomia.

my heart sometimes pound and race even only from changing position on bed (usually after waking up). could it be because my musle is so weak? also i remember back then when i stand up i used to hear blood rush and dizzy and palp, tachy. (lately i dont remember hear the blood rush but the palp and tachy still happens sometimes and dizzy/blackout when im lacking sleep). i read it was similiar to POTS? but the thing is sometimes it doesnt happen and i was fine standing up. and ive never fainted for standing up.
my hand and feet get cold and sweaty lots of times. i expect maybe it was due to circulation problem?
and sometimes i get my heart pounding when i enter sleep. (back then i also could hear the blood rush although i think it wasnt real) since 2-3 years ago i develop another problem :( i could get tachycardia randomly in my sleep which is scary. it lasted for like 10 minutes. it puzzled me how sleeping got so many connection with my issues.
i also have many digestive problems and food intolerances. i got cramp so easily and muscle stiff, sore.i also experience sleep apnea sometimes (throat muscle feels closing the airway). and randomly attack where i stop/forgot to automatically breathing in sleep and then get awaken breathless.
i get some dizziness after riding an elevator.
what confused me is could it be dysautonomia eventhough it didnt happen constantly? (it could get better and worse overtime)
i also expect theres maybe a problem with hormonal.

[KisekiShiawase]

Hello! Thank you for replying here i appreciate it :D
the tachycardia was detected through my ecg handheld monitor since im not close to a hospital so its hard to detect it i own an ecg handheld although its only 1 lead and not as good as the one in hospital or holter but it detected the fast heart rate.
the sleep apnea hasnt properly diagnosed/detected cause it also happens randomly so for that matter i was thinking of buying an oximeter hoping it helps.
yes ive been prescribed different beta blockers but the one i got the most and used for years was propranolol. (despite the effectiveness) lately the doctor changed it to bisoprolol and i guess i noticed a difference although i was kind of confused, i always thought: werent all BB supposed to work the same for HR?
however the caused for my issues still undetectable :( so ive been trying to gather info about it.

[Heiferly]

Can you clarify a few things for me? Did you have a polysomnogram (sleep study) and that's how they diagnosed the tachycardia during your sleep and the sleep apnea, or how was that all diagnosed? Also, what did your doctor say when you told them the beta blocker wasn't helping? Did they ever try a different beta blocker or adjust the dose?

[KisekiShiawase]

i forgot to add. for the heart problem other than ecg, holter, echo they test for t3, t4, tsh. blood count, to suspect anemia, blood calcium, but its in normal range.