I posted at length in your other thread. In this thread I just want to say that you need support. It is not unusual for people with health issues to see a counselor. In the absence of parental support that might be helpful for you now.

I discussed possibilities from my experience and that of my daughter at your age in the other thread. I would add rheumatology/ autoimmune testing to neurology and cardiology. Get yourself a Kardia for home EKG to document or reassure. Functional/integrative medicine and PT can be helpful.

Consider Lyme, whiplash/cervical spine issues, sciatica. You could be having separate issues or one issue with many aspects. In our experience this can improve (with appropriate treatment) but addressing it with multiple doctors and frustrating testing can be stressful and support is needed. Sounds like your heart is okay which is good news! Keep us posted!