Sounds like gears shifting when I'm not
When I increase pressure when I am starting, increasing speed or going up slight incline on my Northway FE Columbia bike it sounds like I am changing gears when I am not. I have only been riding a bike for 6 mo. I took it back to Sports Authroity and they can't find anything wrong with it. However, I think they just put it on their rack and spin the wheels. It happens with quit frequency.
Sounds like you have a worn chain and/or cogs. Easy to check the chain wear with a chain wear indicator tool. Any dedicated bicycle shop should be able to help you.
You gonna eat that?
Yeah.... the Sports Authority won't be very helpful at all. That said, it could be something as simple as a minor adjustment of your shift cable. I doubt you've already worn out a chain. If you can find the adjusting nut, you may try adjusting it maybe a 1/4 to 1/2 turn in each direct to see if that helps. (Keep track of how far you turn it so you can go back to that setting if it only makes things worse).
If you aren't adventurous enough to mess around with it yourself, just take it to a (real) bike shop.
I also doubt the chain is worn. Sounds like the cable has streched and you just need to tighten the slack. Pretty typical stuff. Google Park Tools and look at their how-to section for rear derailleur adjustment.
Just putting it on the repair stand and pedaling may not have enough pressure to recreate the sound.
Bicycle Repair Man !!!
If it is a new bike the housings have probably seated themselves and caused a little slack in the cable... there is an adjustment barrel at the rear of the deraileur (if you are looking from the rear of the bike) and I would turn it back / left a quarter turn and go for a ride to see if this remedies the problem and if not try another quarter turn.
You can visually check the setting by looking at the chain when it is running on the smallest cog as it should be square and should not be pulling the deraileur cage left or right... you will see how this barrel adjustment affects that.
Micro adjustments can be done at most levers, but not all.