Firstly, Patgabz and Lady_Zeb made some good points. You should look into reading more about this subject. You'll find a lot of things if you vary up your search phrases in Google.
The chakra tests are far from definitive. You shouldn't place so much weight on them. As for the pose, don't worry about that. The point of yoga is oneness, the break the yoke, if you will. You're bringing your mind, body, and spirit into a single space to grow together.
You get out of yoga what you put in, what you're willing to do. Courage is what yoga is about. The more you're willing to let the worries of the world that weigh you down go while doing yoga and be adventurous, the more you will go. It won't be an immediate transformation, it's something you'll need to do regularly and measure over a period of months. And often it won't be you who sees the transformation until everyone else in your life has pointed it out to you. You're too close to the source, if you will.
Now, to answer this point of your later post: " School is the problem. There are teachers and bullies that I can't escape. "
People who are undergoing spiritual transformations find themselves in this situation. Their co-workers, family, friends, etc. will get agitated, suspicious, more likely to try and sabotage their life. They often won't know that they are doing this to you. It's part of their baser nature and rooted in the first two chakras. They are trying to protect their world from a greater threat.
This is because people can't handle unconditional love. In this day and age, it's alien to them. They feel conditions should be placed on it and someone who looks at them with love and understanding, someone who can "see into their soul", as they sit and talk with them is a scary thing. I'm not saying you're at this point yet, but you've started on the path.
You shouldn't be afraid of this. You're in the perfect environment right now to get use to the idea of dealing with people's root natures. You don't have any obligations outside of learning, no job, no bills to pay. Consider this a blessing in disguise. A challenge to grow.
Now that you know this, you can better address your problem.
Shielding blocks you off from people. At least the generic one does. People will see you as being distant, hiding something. This isn't what you want to do at first. You want to specify when creating your shield that you only want it to reflect negative energy and attacks towards you, but let your love and emotions out to the world.
Once you do this, don't be afraid to open your heart up, let your love overflow from your body when you're talking with people. Smile and feel fondly towards these teachers and bullies as they are trying to tear you down, but don't be discouraged. The first few times will be hard, but you'll get better at seeing their actions for what they are: misplaced aggression. They are trying to compensate for their life lacking in other areas, so they try and take power/control here.
Eventually they will come around. You'd be surprised at what accepting people in spite of themselves will do to change them. People just don't give it enough time to work. Now, having said this, do watch out for those who try and take advantage of a loving and caring nature. You can't change those people.
You can Google "Google-Fu" to get some ideas about how to really open up your ability to get answers on anything from Google.
In this instance, you might try things like, " yoga to open the heart chakra ", " mudras for the heart chakra ", " heart chakra meditations ", " heart chakra seed sound ", etc.
By no means are all these links accurate on everything. They each contain bits and pieces which may work for you. You'll need to do a lot more study and practice to find what will help you. Different perspectives will help give you insight into this.
