Is there any condition that could cause both neutropenia and hypothyroidism? all orderedblood tests and bone marrow biopsy came back normal/negative.

Unrelated: Hypothyroidism is very common condition, so it is not uncommon to have other conditions that can coexist independent of each other. Neutropenia is often caused by bone marrow damage of some kind or other, although on rare occasions it can be congenital(since birth, cause unknown). The degree of neutropenia matters. So you should give us all the numbers of your CBC...such as WBC count & Neutrrophil