My friend's husband is a manager at a chain resturant here in PA, he is having an affair with one of his bar servers, could she sue the company for pain and suffering or somethng????
She could file the complaint, but she'd lose the lawsuit and might get hit for sanctions for filing a frivilous claim. There are two problems with what your propose. In order for the employer to be liable, the actions of the employee must (1) be a wrong that she can sue for and (2) must have been an act that is within the scope of employment. This fails on both counts.
The server isn't liable for anything because PA, like most states, has eliminated the old torts of alienation of affection and criminal conversation that used to allow someone to sue their spouse's lover as a result of the affair. Nor does your friend have any civil claim against her husband for the affair. Instead, that's settled in any divorce action they may have. Thus, there is no civil claim against the employees of the restaurant here, failing the first test.
Second, even if PA still had an alienation of affection cause of action, the employer is not liable because the affair is not within the scope of the duties of the employees. In other words, the employer didn't hire them to carry on an affair. They do that on their own time. Thus, this fails the second test, too.