To fully understand your cat's behavior and properly solve the issue of problem scratching, I recommend reading this article in its entirety. The links below will advance you to the designated sections if you wish to review. Reasons not to declaw.
Scratching is natural behavior for cats.
Provide your cat with an appropriate scratching post. How to get your cat to prefer the post. Trimming your cat's nails. An excellent alternative. Your Sofa and your nerves are in tatters.