it is very difficult to answer without knowing the details. In the last years many courts in Germany decided positively about people, who previously got asylum in Greece but left this county because of bad living conditions. In many cases such people got a ban on deportation to Greece from the court and could obtain a residence permit in Germany. But there were also negative decisions in similar cases.
The problem is that your case is probably fully rejected (it is not very clear from what you wrote, if you didn't make any appeal to the court against the negative decision of BAMF or the court decided negatively in your case.
If you are fully rejected, you can consult a good asylum lawyer or a special councelling center for refugees in your area and ask them what is possible in your case. With a new asylum procedure you can only have a chance if you provide evidence that the situation in Greece for people with asylum status has become worse. The other way is through integration (work, Ausbildung), naturally if you are not prohibited to work. There are many different possibilities which are very individual, depending on a concrete situation.