Diagnosed with high bpm at resting point and chest pain when lying down, what's going on?

Possibly: Anxiety can cause excess cortisol, os adrenaline secretion which can cause a number of symptoms, including dizziness, lightheadedness, rapid heart beat palpitations, chestpain, headaches, etc. Try calming yourself down by concentrating on slowing down your breathing over a few minutes if this doesn't help, see your primary provider for further evaluation. Good luck!