Chair pulled out from under me.

If a chair was pulled out from under you, then you may have a personal injury law suit--in negligence, if it was done carelessly, or for tortious assault if it was deliberate. Not knowing the facts, we can't say how strong or weak your case is, just that you might have one.

In terms of your rights, you have the right to not be carelessly or deliberately injured, and if someone violates that right, you can sue them for the monetary damages you've suffered, such as: out-of-pocket medical bills, lost wages or income (if you missed work), the cost of any special shows or canes or crutches, the cost of any assistance or nursing care, the value of anything else (like concert tickets or a vacation) you could not go to. You might be able to get pain and suffering, if you were badly injured; it's *very* doubtful you could get any punitive damages.

Before bringing a lawsuit though, bear in mind that retaining an attorney and filing a case can be expensive, and if the case is contested--if the defendant doesn't quickly settle--the costs can add up very fast. Depending on how badly you were injured, it might not be worth it. Are there other sources of compensation you could look to first? For example, if injured at work, your company's workers compensation policy?

In terms of protecting yourself, make sure you don't make any statements, particularly in writing (and including online, such as on Facebook) that either contradict your account of the accident or let the person who pulled the chair out from under "off the hook." When we talk about events, it's hard to always make sure we're saying the same thing, the same way, and contradictory or out-of-context statements can hurt a case.