Basically when I press the mouse button 5 it works fine, and when I press mouse button 4 it works fine too, however when I hold shift on my keyboard (huntsman elite if it matters) the mouse button 4 acts as mouse button 5, with mouse 5 being unchanged when holding shift. Sorry for odd explanation but the mouse is also quite old so it might just be time to retire it. Thanks.
also this is somehow tagged with basilisk ultimate, i just have the basilisk