my right tail lights, all my three bulbs are working properly but on the left only the 2 bulbs which are behind the (red) are on and the (yellow) doesnt work but it only works when i put my flasher on, can someone tell me what does that and how i can fix this?

 

the amber bulbs in the tail lights should only light when your turn signals are on.. if one of them stays on, then there's something wrong with that.

 

so than what you are saying is that its on my right side that is wrong?

 

If the amber light on your right tail is always lit, then yes. Most likely a chop job from the previous owner.