Hair braiding is an art. There are numerous ways of braiding down your human hair and is all depends on the type of install you are getting. Personally I am a fan of the circle braid, however not everyone can use it. The circle braid technique enables a versatile install that you can wear up in a high ponytail, but you need to have at least 3 inches of virgin hair to use that method successfully. Vixen install is another popular method.
A good human hair weave braid down should feel comfortable and not be too tight. If it is not done properly the braids will cause tension on the hair roots and cause pain and in worst even cause long term damage and hair loss. If your braids feel too tight you should immediately unbraid and redo the braiding part. I ask my clients while I am braiding if they feel any pain or discomfort.
If you are unsure on how to braid down your hair you should definitely seek professional help. I am famous for having very light hands when braiding so I did a video on you tube explaining the braiding technique of Brazilian hair used for a circle braid. By watching it you would at least know what to expect when going to a professional weaveologist.