Originally Posted by
IK_biker
NCEL
You have neither the understanding nor the skill needed to fix the issues you describe.
Those come at the price of hands-on experience which can not be gained on the interwebs.
You can not be helped on this forum.
Going to a bike shop is your only option. Otherwise, you are going to ultimately ruin the bike, get hurt - or both.
I don't think these problems are that serious. Anyone with basic mechanical aptitude can quickly learn basic bicycle repair.
I think the solution to Problem #1 has already been explained by the other members here. The OP needs a new quick release. Those are cheap and easy to install.
Problem #2 could have several causes, all of which are easy to fix. New chains are cheap and easy to install with a $10 chain tool that a bike shop can show the OP how to use. If a new freewheel is required, the bike shop can install that for a small amount of money. Cleaning the derailleur would be simple. New shift cables and housing are cheap and the shop can install them for very little money.