Boston Terrier is defying all forms of discipline and obedience?

hes a year old and i haven't had any problems from him for like 3 months but now hes being a bad dog. he is potty trained and knows not to go in the house, but since christmas hes been breaking into my back bedroom and pissing on everything, marking not big puddles just like a quick stream, and this morning he took a big crap right on a customer's fabrics(i do upholstery). hes also been going into the trash and getting stuff and ripping it up. i trained him not to do this stuff 8 months ago. a firm no has no effect on him, let me repeat that for the diehard nonbelievers in , SAYING NO DOES NOT WORK, YELLING NO DOES NOT WORK, SCREAMING NO DOES NOT WORK, he simply looks and me and continues tearing stuff up. he only responds to s, in which he pees all over the place. im boarderline taking him to the pound. for a breed of dog thats suppose to be really smart he sure isnt learning.