Have a two sinks in my kitchen right now both sinks are backed up. Hel

Usually both sinks drain into the same elbow under the sink, so most likely it is at or below where the drains come together. If you can, try to take the water out of the sink without the disposal as much as possible. Put a half cup of baking soda into the drain and follow with a cup of straight vinegar. You should hear fizzing and see bubbles. Let them work until you don't hear the fizzing anymore. Try putting in just a small glug of vinegar to see if it starts fizzing again, if yes, let it fizz. Boil up about a gallon of water and try putting just a little down the drain to see if it drains. If it doesn't, empty as much liquid out of both sides of the sink that you can, now you clear out under the sink, get a bucket and start loosening the pipes to find the blockage, it could be the elbow is packed solid. Take the pipes from the disposal off to make sure they are clear, as long as you are down there. Clean out the clog if you find it and put it back together. Run the baking soda/vinegar/boiling water through to make sure any little bits of the clog are cleared through. If this didn't work, you may need to snake the drain to get rid of the clog.

Also, never ever pour grease from food down a drain. Even though it may be hot or even if you run hot water to rinse it down the drain, it cools in the plumbing pipe and builds until you have a blocked pipe of a clump of solid grease.

I would first try a plumbers friend. You can get them at the hardware store. Then if that doesn't work, go to the hardware and ask for someone to help you find the best product to put down the drain to clear it. That is what my husband did and it cleared the drain quickly and cleanly.

Double sink I hope. First try a plunger. 1. Cover one drain and plunge the other. 2. Cover the left drain with a damp cloth. Have another damp cloth ready. Pour some baking soda down the right drain. Pour vinegar down the right drain and immediately cover both drains and hold down. The reaction should force the clog through. If this does not work you will have to remove the P trap and possibly rod it through.