Hi, acute multiple joint pains do not require all these investigations, has he had fever now or in the recent past, are there any other signs, do he have morning stiffness are more important for us to know, meanwhile probably his MRI may also come normal. Take Rest, Tab Paracetamol 500 mg three times a day. Local heat on the joints by hot towel. give it some time to heal, I hope you will get alright, but be vigilant on any recurrance of symptoms, also lead a healthy active life to ward of arthritis.