Paper jam

I have hp deskjet 3050, I have not had any problems out of it until now. It keeps telling me that I have a paper jam, I have checked the back of the printer where you put the paper in. I also have opened the cleanout in the back of the printer, I cannot find the jam anywhere. It will not pull the paper through so I am guessing that the jam is in the back but i cannot find it for nothing. Please help