I just bought a house. The beginning of last month the plumber had to come out and rod the toleit. Everything was fine. Now the other day the laudry room sink backed up. I heard a gurling in the toilet and it was bubbling. Then everything was OK. Next I washed some clothes and everything seemed fine but I looked in the toilet and saw soap bubbles. What can this be and what should I do?

Call the same plumber back and ask if he guarantees his work, no seriously, call him. Most plumber would stand behind their work for more than a month. If he says no then ask him to rod it again at a lower repeat customer price.