It's more or less your boss's job to create a hostile work environment. A hostile environment is not illegal, nor is workplace harassment in general or bullying. There is no legal action for "causing stress" on the job.
Although you cannot sue your employer for creating a hostile environment, it certainly can be part of an underlying discrimination claim. For example, if the environment is made hostile due to harassment on the basis of sex, religion, age, race, national origin, or, disability, then you definitely have a case.
Some employees have attempted to raise hostile environment claims under the Americans with Disabilities Act, under the theory that the employer's behavior caused the employee to suffer mental illness (such as severe depression), and that the employer failed to accommodate his disability. These claims have not been very successful so far.
So if you experiencing stress on the job, if it doesn't involve discrimination, then you are probably going to have to suck it up or find another job. By the way, according to ABC News, the least stressful job in 2013 was a university professor. www.abcnews.go.com/Business/top-10-stressful-stressful-jobs/story?id=18115397