the typical symptom you describe is burning sensation along with body ache
in ayurveda it falls under category 'dhatu kshay' which is nothing but more catalytic activities in body than anobolic activities.
the problem must be chronic .
a good nutrition is the key . Is ther any major illness like typhoid
or any other
you haven't mentioned about your weight .
ayurvedic anabolic medicine (oaj varhak) and some specific panchakrma treatments will solve your problem and no wonder the investigations are uneventful as the pathology lies in body metabolism
feel free to ask or mail at
wish you helath !