Hi I have a problem with my rear lights not working (side lights) I have brake/fog lights can anyone give me any ideas as to what my problem could b plz

Do you have a constant brake lights on when your lights are on do you mean ?

If so be a round bulb connected somewhere, but worth checking them all anyway for a wrong bulb or blown bulbs, also check the fuse. But I'd have a guess it's earthing somewhere and as I said bulbs the biggest fault.  

Might be relevant might not but I have a switch on top of my steering column. Mine got stuck and my rear lights wouldn't come on so worth flicking the switch to see if that helps if you have it