Do people on parole have civil rights opposed to civilians that are not?

It appears you really have two questions here and I'll attempt to answer them.
Do you maintain your civil rights on probation/parole? Most parolees/probationers give up certain rights as part of the general requirements of probation. The idea that an officer can come to your house day or night and search for violations is a prime example. Every state is different in the limitations of these types of intrusions. Review the terms of your contract for probation/parole and it should state these rights you have traded in exchange for supervised probation.
Your second question is more about violating probation. People such as this private investigator can't violate your probation or send you to jail. Your probation officer is the only one who submit an affidavit of violation to the court. If that happens, you can admit the violation and enter some sort of agreed upon plea or you can deny the violation and proceed to a hearing. Violation of probation hearings are a mini trial but without the jury. The judge decides. The state must still present evidence and call witnesses. The state must prove that you INTENTIONALLY violated your probated by a proponderance of evidence (at least in FL & GA). A proponderance of evidence is less than beyond a reasonable doubt. Most people liken this standard of proof to 51 percent. Put your hands out in front of you side by side with your palms facing up. One palm represents the state and one palm represents the defense. If your hearing ends and both sides are even like your palms are, then the defense is the victor. But, if the state's hand moves up just slightly, then you lose and could face the remainder of your probation in prison.
You should probably try and speak with your probation/parole officer if you feel threatened by your exgirlfriend or this private investigator. Or you could consult the attorney who assisted you in the charge that landed you on parole/probation or you could consult another attorney. Good luck!
Disclaimer: I am licensed only in GA & FL. The information provided herein is only meant for educational purposes and in no way renders information legal advice.