hello everyone
i have a question that is pretty important for me to know as quickly as possible so i would really appreciate the replys.

I want to know how to perform a powerful side kick and a powerful back kick?

Meaning that i want to know every little movement on performing both of these kicks
everything from the position and movement of your feet to the excact movement of the body its self

As with your other post.

Keep the knee high and close to the body. This should encourage easier movement and balance. To assist this I keep my ankle cocked in the position I want it to arrive in.

So for side kick, the bottom of the foot is curled to face the side of the knee, big toe up, other toes curled round to form the "sword". For the back kick, keep the the foot up, so the bottom of the heel faces directly down.

Try leaning into the kick (side only) and keep your arms close to your body.

Re-chamber your kick before moving, this will aid balance and movement.

Power is generated from the hips.

Additional forward movement will assist this, but also don't forget to pivot a little on the supporting leg to get increased distance and power.

Practice.

Budo.

Whats the urgency? If you don't mind me asking, its just to develop good kicking power takes time.

If you go to http://www.stadion.com/ they sell a video called 'Power high kicks with no warm up'

This is an excellent video to show you how to perform a range of kicks at high power (with the added benefit of no warm-up).

I have a break test coming up and unlike my rounhouse, snap kick, ect.
my side and back kicks are really weak
so i was just trying to find out what i was doing wrong b4 my test

Shouldn't you really be asking your instructor these questions?

Or is he a little unapproachable?

Not too sure about the side kick but the back kick should come straight back after chambering the leg. Alot of students either dont chamber or they bring the leg back with the shin not directly below the thigh and the knee not pointing directly forward. 2 benefits of this are that if the target is directly behind you (where he should be if you have turned properly) a kick straight back will be more powerful than a kick coming from an angle....the second benefit is that if your legs are together your opponent cannot give you a swift kick to the nuts when your back is turned ;-)
Just before contact a slight twist of the hip towards the target should give you enough power. Another mistake people make is that they lean their body weight away from the target. Although the body is bent forward (away from the target) your body weight should be moving towards the target. This will help you drive through the target/wood/ribcage ;-) If your weight is driving through the target then you will continue forward on the offensive. If you lean away from the target there is a good chance that you'll absorb as much of the force as he will and you'll probably move back away from your opponent possibly putting yourself on the defensive with little balance and your back to your opponent.
My instructor (7th Dan Korean guy) has recently told me never to use my back kick against anyone less than a black belt...apparently i've got the technique down to a point where I will seriously damage/destroy anything i hit...might be a good thing for breaking or in a street fight, but not against a fellow yellow belt.
I guess what i said above about leaning your body weight into the target even though you are physically leaning your body away from the target might also apply to side kicks..i've never really thought about it.