She might only see you someone whom she can trust with her secrets. Despite your effort of flirting with the girl physically and verbally, she does not really respond to anything.
This simply means that there is no evident sign of attraction probably because she only sees you as a friend and nothing beyond that.
Don't take this personally, but you may be in the friend zone and just don't realize it.
Here are the some friend zone signs to keep in mind when trying to get a guy to like you.
The more likely reason behind why it feels like he put invisible handcuffs on you is that he may be friend-zoning you. Accidentally drop something in front of him, preferably at a time when he is not looking. If you get lucky then maybe you will break the touch barrier with him.
In the worst case, he will not notice and you will be the only one doing the picking. It might not be much, but— do you think he will notice?
Many men these days are trying to avoid friend zones because they are aware that being in this position can really be frustrating and draining.