You have asked some important questions. Pheochromocytomas are rare, catecholamine-secreting tumors arising in the adrenal glands. Recent studies have suggested the frequency of mutations associated with isolated pheochromocytoma is higher than previously estimated. It is estimated that about 20% of pheochromocytomas are due to hereditary causes.
There are 4 different hereditary cancer syndromes (neurofibromatosis 1, multiple endocrine neoplasia type 2, von Hippel-Lindau syndrome, SDHB/SDHD) in which pheochromocytoma is found. It may help you to meet with a genetic counselor to take a complete family health history and then discuss your options for genetic testing. There is genetic testing available for all 4 of these hereditary cancer syndromes, but it is important to talk with a genetic counselor about the benefits and limitations of the testing.
In all of these conditions, only one parent needs to have a gene mutation, for the children to be at increased risk. Your chances to have a gene mutation are not increased because your mother had a pheochromocytoma while she was pregnant with you. Having the significant family history of a pheochromocytoma may increase your risk, and it is important to have this evaluated. You can find a genetic counselor in your area using the website of the National Society of Genetic Counselors (NSGC).