I had a similar issue with my printer. Middle of the night, it started jamming. I had to take off my hotend and remove the nozzle. Filament got dried up inside it. Try maxing out the temp and feeding filament through the tube into the hotend to unstick any filament inside. DO NOT LET THE FILAMENT FFROM THE TUBE MELT IN THE HOTEND. You will have a major issue if it melts.