Pleading the fifth in court refers to the fifth amendment correct? So based upon that if you are testifying against someone in court and you do not want to answer you still have to because the fifth amendment refuses you the right to incriminate yourself.

The fifth amendment states that you may refuse to answer a question in a court of law, should the answers perhaps incriminate him. If the person chooses to testify, the fifth's privelege, and inferences can be found where there is refusal to answer a question.