hi. been having some odd pain in the bones. first had it in my left arm , could barely keep it up for few days, then pain in the chest bone, was hard to breathe and every time the the pulse went of in it s normal rithm, it felt life a sharp pain in the bone chest, then had problems with my right s arm elbow . every time my elbow touched hard surface, like if i was suporting my head with my arm on the table, it was painful. then pain in my back but i never gave it any attention till 3 days ago when both my knees out of nowhere gave me the same problems. what could it possibly be? thank you