Your fender well has come loose.
The plastic around the screws holding the pieces together has probably torn, causing it to come loose, and sag down onto your wheel. This happened to my right side and is still broken.
Depending on how many screwholes have been torn, you can temp fix it by pushing it back into place, but it likes to come loose often. If your a ghetto repairman like me, black ducttape ought to help do the job. Best would be to repair the plastic around the screwholes but that's gonna either cost money or take a long time.
Either that, or you have tires that are too large and they are rubbing against the fender well. My bet is the fender well plastic just broke off.