Hi My Son Has Been Sick Off And On For

hi my son has been sick off and on for the past two months he is 12 years old he has been sneezing watery eyes coughing sore throat headaches stuffed up really tired no fever i am getting concerned i have already taken him to the clinic 2 or three times already they said that he had a viral infection but for two months i dont think they are supposed to last this long is this normal