Do doc use medicine to treat pt in physical medicine n rehabilitation? or only machine n exercise help pt?

All options : Physical medicine and rehabilitation physicians use all the options available to treat function problems. This may include prescribing medications, physical or occupational therapy, speech or language therapy, injections, etc. It all depends on the problem being treated.

They do a lot: first they identify the problem, then they use medicine, exercise, modalities, injections, activity modification suggestions, bracing, equipment, psychological treatment, help coordinate necessary evaluations/studies, talk to surgeons, etc. http://www.aapmr.org/patients/aboutpmr/Pages/WhyARehabPhysician.aspx