What types of muscle myopathys are inherited&if tested positive for a myopathy but don't know what one how do I find out?

Physician can tell. A huge number of myopathies are hereditary but some of the most common and troublesome ones (polymyalgia rheumatica, inclusion body myositis, polymyositis / dermatomyositis) seem to strike at random. Your physician has a duty not just to tell you the diagnosis, but whether it's hereditary and where there's a risk to others.