My 10 Year Old Son Has Been Getting Pains Frequently

My 10 year old son has been getting pains frequently around where his appendix is and his hands have also been shaking, I took him to the Doctors on Friday but couldn't identify anything. Yesterday in school he had a slight nose bleed and when I got to school with him this morning he was upset because his shoulder was in pain, he describes the pain as electric shock going through his body.