I have a bad odor coming from my kitchen sink. I have used vinegar and baking soda, drain cleaners and ran water. What could it be.

Just a sink or is there a disposal? If there isn't a disposal, you probably want to talk to a plumbing expert here, maybe there is some sort of issue with the sewer backing up or something. Just find someone in the plumbing area and send them a message.

Answer Ladyvipers questions. The receipe is 1/2 cup baking soda plus 1/2 cuo table salt mixed and dumped into the drain followed by a cup of vinegar. Allow to soak over night and then flush with two large, very hot buckets of water. Is that what you did, it should clean out the sink and would work on a disposal but you must then treat each drain equally. For disposers I also periodically dump a half gallon of ice withwater running full blast and then turn on the disposl.

Just find someone in the plumbing area and send them a message.
Hey Lady! We're in th plumbing area, send us the message. Everybody's got a favorite recipe for flushing out a smelly drain. Mine is bleach.
Dump a 1/2 gallon of bleach down the drain and let it set overnight. Next morning flush out the drain with two large pans of boiling water.
For the disposal; after the ice, cut a lemon into quarters and run them through the disposal. Everything smell sweeter now? Good luck, Tom