Quote Originally Posted by greta View Post
When I first got the bike I fell real hard when I went from the road to the sidewalk and my back tire followed the curb division rather than me. The shifters lost paint on the ends of them or I would have asked if I could return and upgrade.
Which side did your bike fall on when you had your fall? If it fell "expensive side" down (that'd be the side with derailleurs) and the rear derailleur made contact with the ground, it is possible you could have bent your derailleur hanger. This is a little bit of sacrificial bracket that your derailleur is attached to and then attaches to the rear of your frame. It is supposed to bend/break before your frame does! And then you replace it, which is a lot cheaper than a repair to the frame.

I leant my bike on a wall and it fell over (oh so gently) and it landed on and bent mine ever so slightly. It will (and did) result in sketchy gear changing on the rear (if only slightly bent) right down to gawd-awful horrid not-changing/noisiness if it is really bent (like when some gumby ran into the back of me when he overshot the rest stop on a group ride on time).

While I think the bike shop has been a bit ordinary in their treatment of you, if they haven't been told you have had a little stack, they might not look for a bent hanger and may find it difficult to diagnose the problem and fix it, particulalry if the problem is only slight or intermittent when under load. But if the hanger is bent, it is a quick and very simple fix and your components should work like new (as they should really).

Good luck!