I am assuming a wide door w/2 springs??? First test, disconnect the opener from the door and manually operate the door. It should go up/down evenly, with about equal force, and stay at mid travel if you let go. I am assuming it does not do that?? You should be able to watch the springs wind/unwind, that should tell you what the problem is, if it is springs. But CAUTION, winding torsion springs can be very dangerous if unsure what you are doing.
There are other things on the door that can squeal/squeak, so watch for binding hinges, door binding on the garage framing, etc.