My kitchen sink is very clogged,I plunged the right side and the left side goes down but as soon as I take the plunger off the right side water comes back into the left so I'm keeping the right side stopped up with the plunger. I've tried liquid plumer twice and nothing seems to help.please help me it's really frustrating.

You have a blockage in the horizontal drain line in the wall. Put on rubber gloves and protective glasses and dip and sponge the lye water out of the sinks. Remove the trap, CAREFUL!! don't get any in your eyes. Now send a snake up into the wall. You will run into a elbo about 8 inches in but once past that all the cable you'll have to run out is 6 foot more. Afterwards flush the line out with a sink full of hot water. Good luck, Tom