I got a hit n run on my 90 civic on the rear driver side.ever since then my car smell like exhaust and i cant find if its leaking anywhere.where else can it be coming from?

 

You're exhaust is probably bent causing a leak. Take it to a muffler shop, explain to them what happened and I'm sure they will be able to find it and fix it.

 

The hatchback might not be sealing tight to the body if it was wrecked.
Can be adjusted some using the striker and or latch

easy way is to take a piece of paper, and close the hatch on it where the seal is, and slip the paper and see if it is snug or loose.
May need a BFH to get it good, or just a screwdriver and move the striker.