My transmission wont go into the fifth gear.
My car has a manual transmission.
This may suggest the transmission synchros may be wearing out. Your transmission has small gear synchronizer rings that help to move the transmission in and out of the various gears. When these begin to wear out, you may notice it hard to shift in and out of gears as you describe. You may also occasionally hear a bit of a grinding sound when trying to shift from gear to gear. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your transmission.