Tachycardia, Chest Pressure, Taking Inderal. Diagnosis?

hi iam female single 30 years old my job is a dentist since 2009 till now iam suffering from tachycardia i did many tests for thyroid gland , ecg , eco , holter all the result were normal but iam still having tachy cardia when waking morning or after nap ..i feel pressure in my chest when wearing somthig narrow ,, even i cannot sleep on my left side cause feeling pressure and spasm when iam sad the spasm in chest is increase or when i feel tired ,, or when feel scary,,and iam emotionally sensitve,, for ur information iam taking inderal or propranolol for decreaing heart rate i want to know what is the diagnosis of my case and do i have somthing seroius