I am 21 years ols, and o I have noticed that my left butt chick is lower than my right one. I tried for the last 7 weeks to concentrate on "lifting" it, but I can't seem to see any differences. What should I do?
This sounds like a very common muscular imbalance which can be brought on by tendencies in your sitting position, standing position, and a lot of other factors.
What NOT to do
You might be inclined to work one side more than the other to catch up, but that is a mistake!
Let's say your left buttcheek is sagging because the right gluteus medius is stronger than the left one.
If you start working out the left side more than the right side, you might end up with the same problem, but now your left gluteus maximus is stronger than the right side one, and you're back where you started.
What to do
You should do squats. It's an exercise which works your gluteal muscles a lot, and since it's a symmetrical movement, you will be training both sides until they are equal, avoiding the mentioned mistake.