If your plumbing starts to give you fits, you may decide to try and make some of the repairs yourself. There are several plumbing mistakes many people make that end up costing them a lot more than if they would have just called a plumber in the first place.
Applying too much pressure on a struck shut off valve will not solve the problem. Trying to force a slip nut or piece of loose piping can result in damage to not only the pipe you’re working on but others that are close to it. Take it easy and try to work it loose. Never force it.