can you personally contact the presiding judge if there are conflicts/problems involving a current lawsuit

This question is very hard to answer without more facts. At a minimum, someone trying to give you a confident answer here would need to know (a) what state the proceedings are in, (b) what sort of proceedings they are, (c) what your connection to the case is, and (d) what sort of conflicts/problems you're talking about.

The answer you get might be very, very different if, for example, you're a juror in an on-going trial than if you're a LITIGANT (someone suing or being sued) in that same trial. It also matters whether it's a civil or criminal proceeding.

About all I can offer, given the vagueness of your question, is this: Judges are restrained by the Canons of Ethics from engaging in "ex parte" contacts -- meaning private contacts, without having given notice to all parties in interest and an opportunity for them to observe and be heard. So except for a very few exceptions (including an important one for jurors), making a contact with the judge other than through the formal, public channels that require notice to everyone involved is likely to result in the judge refusing to even consider what you've said; and it might well lead to LOTS WORSE CONSEQUENCES (as would be true if you're one of the litigants and you're perceived by anyone as trying to "lobby" the judge secretly).