Oh, Oh, you are really in the middle of this and it sounds like you are alone without some support to help you out and reason with the adults that need to help you.
Coming from a Mom, now; you really need someone to help intervene for you.
Is there a school nurse you could go to see and talk to about the pain you are having in your spine and maybe talk with your parents from a medical standpoint?
I know that the school doctors are not always helpful, but sometimes a school can have a good one to turn to for someone to talk to and intervene on your behalf with your parents.
How about your guidance counselor at school? Do you have a good one that you could talk to that could talk with the school nurse and then your parents?
I don't like the sound of your gymnastics coach. A coach is supposed to be supportive of their students under them, and I know that first hand as I've coached soccer for many, many years. When a player asks to watch them with something, I'm right there to do so, no questions asked and no doubts as to a reason why I should or shouldn't.
Your coach should be doing the same thing and if your coach isn't, and ignoring you and the pain you are having in your spine; Well if It where my son or daughter and I knew about that, the coach would get a long, loud earful from me and my kid would no longer be under the coaches direction anymore.
As for what your coach said, he/she has no knowledge of anatomy and physiology at all. What was said is 100% wrong, and a HS student in an anatomy and physiology class would apparently know more than your coach.
If, as your coach said, you have not ab muscles, then what you where doing would hurt your spine period. Forget about any spine pain that you have already. Without strong core (ab muscles along with quads), you pull on your spine and make it hurt.
The appearance of your abs has nothing to do with the strength of them.
What I do know, is that every time you do something in gymnastics, you are making your spine worse and worse. That is not good.
Poor posture also doesn't help either, but that is not a reason for your parents to ignore your need for help.
Just thought of this idea for you.
You are a teenager and have the right to privacy between you and your primary doctor.
Can you talk with your primary doctor without your parents there? You should be able to do that. Both of my kids where able to call and talk with their primary doctor without me present or even knowing about it if they chose to, and that never upset me to know they could or might do that.
My first concern was their health and welfare and if they wanted to talk with their doctor about something that they didn't want me to know about, I preferred they did that, than ignore the situation.
You need to be seen by a spine doctor ASAP, stop the gymnastics for now and get this problem under control.
There could be many different things going on with your spine, from the fracture you suspect to discs, to even scoliosis.
Please, do something, talk to someone who can help you sort this out and help you get the care that you need.
Fran
If you are in spine pain, then you are not using your core ab muscles correctly, and doing that can weaken them very, very quickly.