Why do I always feel sad about other peoples problems?

Being able to experience emotions for other people's problems shows that you have high levels of empathy and compassion. You genuinely feel what they are going through even though it is not your own personal experience. This means that you care for the person and want to help them in some way. While this might seem counterproductive, being able to feel other people's emotions is a powerful skill that will help you reach out to others and better understand them. It is also completely normal to feel this way since there are many other people who also experience sadness when hearing about others' struggles.

It is sympathy, where you feel like your in their shoes. It helps you to relate to the person. Without feeling that way, you might not know how to help people in need.

This is called empathy. It is a perfectly normal human emotion that those around you probably appreciate greatly. The response to these feeling that I would recommend is to simply be a good friend to them, and help them feel better.

because i attach myself to others problem... to solve it be deattached an can come to right solution

You feel sad about other peoples problems because you have empathy for that person whether you know them or not. Its a bodies natural reaction to feel bad for someone who is having a problem.