I have never used LN, but read about it and I am confused about one thing, if I am send BTC through channel, then receiver exactly know who send this and can in some way check how much sender's balance left and even locate original BTC address that create sender's channel? Only I know that transaction is sent in onion manner, so participants don't know if sender is guy that sends him tx, or if next receiver tx is end receiver of transaction.
You only know the balance of the channels you have open with your peers. And because the payments to you can be routed through other people's channels, you cannot simply get the information about the sender's balance or other sensitive information.
There are no such thing as Bitcoin addresses, you're reasoning from the wrong analogy to understand this. The only things that exist on Bitcoin are transactions and Script, each transaction only references past transactions and they never have a receiver, just a condition specified in Script for being spent.
Start here: https://en.bitcoin.it/wiki/Coin_analogy