Before going to a bike shop:

1. Either, Put your bike on a stand(if you have one), or turn it upside down, or raise the back wheel off the ground

2. Turn the pedals in a forward motion.

3. While turning the pedals, shift the gears

4. While shifting the gears, watch the chain guide to see if it is loose

5. Check to see how much pressure you have to apply to the brakes to come to a full stop. This could be a sign. That your brake cables need replacing. If that is problem, a bike shop would have the time, and parts needed to fix the problem.