Recently I got the Giant Revolt 3 and have been riding it for a few days now. I have lately noticed that there is some rubbing noise when I apply the brakes. If you look at this picture (might be a bit hard to tell), there is a needle or some kind of gauge on top of the brake lever. When I got my bike, I believe they were in the middle, now my left one is all the way to the left, and my right is somewhat off centre. I'm not sure what they necessarily mean, but they have something to do with the brakes.
I called the bike shop where I bought this bike and they told me I would have to pay $60 for a tune up, and I don't plan to upfront that much money right now if it is an easy fix. I believe the problem is that since the bike is new, I might have to tighten up my brakes because the wires get stretched?
The brakes that are on my bike are mechanical disk brakes. If someone could tell me what might be wrong I would greatly appreciate it. I fell on my bike once because of a pot hole and scraped one side of the handle bar, but I don't think this is the cause since the needles were starting to get off centre before I fell.
Let me know if you need more information to help me out. Thanks!