When i touch it, I feel the space, emptiness and under the skin. It is like something is torn apart beneath. It appeared suddenly and caused by probably an over-pushed asana.
Does any of you have the same problem? Do you think there is any cure for this?
Asana-wise, you can try to be less zealous with the neck. In forward/backward bends, focus on bending other parts of the spine. Many people tend to overbend the neck (and in backbends, even the lumbar spine) where we're already quite flexible; no point in overdoing it.