I have seen articles saying costo can be caused by infection, injury, or even violent coughing. I would talk to a doctor to get an official opinion before you sue though; you'll probably also need to have an expert witness that would vouch for the fact that costo can be caused by infection (and that your's likely is) anyway...

I think to sue you would have to prove your Landlord was negligent. Were they aware of the situation?

We are surrounded by molds all the time...tons of spores. You are subjected to millions of spores outside all the time. The current scare about black mold, to me is a bit over the top. Some people are allergic to mold, some are not. It's the people that have high allergies that react. Some could live in a very moldy environment and never suffer one problem. I know all about this, I managed commercial properties for years and years. We often had a lot of hysteria about this and asbestos.

There is much literature on the net about molds and black mold in particular. If you feel like you want to take action, then I would look for the sites where someone successfully sued for a mold situation (most of the time they are settled, at great cost to both parties). I'm afraid it's just not as cut and dry as you might think..sorry.

So, probably the best you could do is get your Landlord to pay for remediation, which they might not do if they find that this mold is not a part of your particular health issues. As a good landlord, he should do this anyway.

That's my 2 cents. I know that when you don't feel well you want to make someone pay for this, but you really need to do your homework first.

Now, to answer your other question, yes, anything like a cough, sneezing...any trauma to your torso could cause costo. But it's also a diagnosis of exclusions, which means that AFTER the doctor has exhausted all other avenues, like with blood work, and other tests, do they settle on the costo diagnosis (or that's how it should work). If your Dr. did not exhaust all other posibilities then they are giving you a garbage diagnosis.

I wish you a lot of luck in your ventures. Take a deep breath before you take any actions.