hi Almir.
I think, as Gussie suggested, go to a GP, who will tell you if you have anything to worry about or not. You have no pain, so it's not really worth paying to go to see someone such as a physio or chiro when you may be worrying about a perfectly normal body.
This is the bit where the top of the back, or the thoracic vertebra, connects with the neck, or cervical vertebra. C7 (C for cervical or neck, 7 because it is the lowest of the 7 cervical vertebra ) at the base of the neck is known as vertebra prominens, and has a much longer spinous process (the bit of the vertebra that you can feel because it sticks out at the back) than C6 above it, or T1 (T for Thoracic or rib-cage area, 1 as it's the top of the 12 T vertebra).
People certainly do get problems here, particularly if they tend to hold their head forward of the ribs, or if they are very round shouldered - your link shows a good example of this.
Anyway! Hope you are ok!
Kind regards,
Sharon.