Why does Jesus feel only certain people that come into physical contact with Him? Luke 8  


  43 A woman was there who had been bleeding for twelve years. She had
  spent all her money on doctors, but no doctor was able to heal her.
  44 The woman came behind Jesus and touched the bottom of his coat. At
  that moment, her bleeding stopped. 45 Then Jesus said, “Who touched
  me?”
  
  They all said they had not touched him. And Peter said, “Master,
  people are all around you, pushing against you.”
  
  46 But Jesus said, “Someone touched me. I felt power go out from me.”


In this passage I can only imagine all these people pushing and shoving against Jesus but this one small gentle touch - He feels so powerfully.

Can we concluded anything about the other people who touched Him, where He didn't feel anything like that?

Were they all not in need of any health that touching Him had no effect on them or Him, does it mean they were all unbelievers, incapable of understanding what Jesus was trying to tell them or something else?

Why does Jesus feel only certain people that come into physical contact with Him?
As Jesus Himself said Luke 8:46:


  I know that power has gone out from me.


So presumably He noticed the touch because at the same moment power had gone from Him.

So to answer the rest of your question, why only this person? Here it helps to notice that this story is also told in Matthew 9:18-26 and Mark 5:21-43, because they draw out different details. (By the way, the quote in your question ends before the relevant verse - the full story is in Luke 8:40-56.)

In Luke (v48) we read that Jesus said to her:


  “Daughter, your faith has healed you. Go in peace.”


And this faith is further detailed in the other Gospels, Matthew 9:21:


  She said to herself, “If I only touch his cloak, I will be healed.”


(See also Mark 5:28.)

Summary: her faith caused the power to go out from Jesus, which caused Him to notice the touch.

To answer your other questions:


Can we concluded anything about the other people who touched Him, where He didn't feel anything like that? Only that they did not touch Him in faith, expecting healing. Indeed, they were a crowd doing what crowds do - crowding (Mark 5:31).
Were they all not in need of any health that touching Him had no effect on them or Him, does it mean they were all unbelievers, incapable of understanding what Jesus was trying to tell them or something else? The text doesn't tell us. The fact that this woman alone (of the crowd) is mentioned as an example in the three Gospels implies that she was indeed an exception - the only one who touched Jesus in faith.