It is inevitable that sometime in your child's dance education that they will say something hurts. This blog post a great guide for parents on what questions to ask your child to figure out what is going on and if they need medical attention.
In so many sports and extra curricular activities, coaches and instructors are not educated at the college level or certified in whatever they are teaching. In most cases this is completely completely fine and the norm in such things as "little league" sports or even some competitive sports. However in dance this should never be the case. Education is extremely important and just as importantly is continuing education and training to always be on top of the game.