I am so sorry you are having issues with your little boy.   It does sound like something medically could be going on.    Has he been around other people in your home other than yourself?    If so how does he act around other people?
 
Does he get annual rabies shots?    The rabies shot can cause increased aggression in some dogs.     
Vaccine Reactions | Truth4Dogs 
Does he go outside very often?    Does he like to go on walks?    How does he act when you offer him a treat?    I do hope you can get him checked out.    He could possible have something wrong that is hurting him and that could make him not want to be touched.