Have you been checked for carcinoid syndrome as well? Ask for a plasma free metanephrine blood test to check for pheochromocytoma. It is the most accurate. There is a support board for pheochromocytoma you can google it to find out more info.
There are several conditions that have similar symptoms as Pheo's. Below is a list of some of them:
Thyrotoxicosis
Primary hypogoadism (menopausal syndrome)
Pancreatic tumors (e.g., insulinoma)
Medullary thyroid carcinoma
"Hyperadrenergic" spells
Cardiovascular
Labile essential hypertension
Angina and cardiovascular deconditioning
Pulmonary edema
Dilated cardiomyopathy
Syncope
Orthostatic hypotension
Paroxysmal cardiac arrhythmia
Renovascular disease
Psychologic
Anxiety and panic attacks
Somatization disorder
Hyperventilation
Factitious (e.g., drugs, valsalva)
Pharmacologic
Withdrawal of adrenergic inhibiting medications (e.g., clonidine)
Monoamine oxidase inhibitor treatment and concomitant ingestion of tyramine or decongestant
Sympathomimetic ingestion
Illegal drug ingestion (cocaine, phencyclidine, LSD)
Acrodynia (mercury poisoning)
Gold myokymia syndrome
Vancomycin ("red man syndrome")
Neurologic
Postural orthostatic tachycardia syndrome (POTS)
Autonomic neuropathy
Migraine Headache
Diencephalic epilepsy (autonomic seizures)
Cerebral infarction
Cerebrovascular insufficiency
Miscellaneous
Mast cell disease
Carcinoid syndrome
Recurrent idiopathic anaphylaxis
I have an adrenal mass and all the symptoms but my mass does not show as functioning on urine tests, so I have been given a 'suspected' diagnosis of POTS.
Do your symptoms have a pattern? Do they become worse with postural changes, standing for a while?