Generally, you do not have that right in the workplace. Only public government employees have free speech protections and those are very limited. As a private employee, you can be fired for your speech in the workplace or outside of it. For government employees, 'Liking' a page may be protected speech under the First Amendment. In a recent case, a federal appeals court decided that a government employee who worked for a sheriff, but liked a Facebook page showing his support for a different candidate for sheriff, was speaking as a private citizen about a matter of public concern. The court found that the employee’s actions did not disrupt the work of others in the office, and his interest in showing support for the candidate outweighed the current sheriff's interest in maintaining effective and efficient public services. In this case, that court viewed the 'Liking' of a page on Facebook as speech or political activity that could be entitled to First Amendment protections for public employees.